The impressive thing is that the audio travelling through 9600 meters of cable has the evquivalent delay of around one centimeter through air! Assuming your FOH is at the end of the line, you‘d have the signal 28 seconds earlier on the console than your hear it. Not the best for tapping delays I guess…
@@DaveRat That's a whole lot of time to bleep out some expletives... or even just... you guys totally suck, I'ma just cue up an mp3 (or even go find a cd) here, eat an ice cream, and play that... before anyone else hears how bad you (they) are live :)
What about if you mic'ed and realtime broadcasted the center of a thunderstorm or a war. Seems nearby people six miles away may hear the broadcast and then the delayed acoustic sound
That is a really cool demo. I've never used a mic cable more than about 150 feet in total (snake + mic cable proper). Back in the mid-70's when I was being taught about pro audio, I was told that normal balanced low-z mic lines could be up to 1,000 feet with no ill effects, and if you wanted to go further, there were a lot of mics that could be switched to a really low source impedance (50 ohms, usually) and these could drive a mile of cable. Looks like the engineers who designed the system way back in the day knew their way around a slide rule!
Back in ‘94 I helped install 8 or 10 12 pair audio mults for an NFL playoff game telecast, the runs were about 1,000 feet from tv trucks to the stage inside the stadium. We also had 10 coax video feeds plus 8 triax camera cables. Today we would run a single tac12 bundle and have spare fibers. The audio guys never whined that I recall. They had to run mics from the stage back, RTS intercom & IFB’s back to the stage from the trucks.
I think this shows that for low and mid fidelity runs, long cables work for signal level. For high fidelity, I have done tests that show there are audible errticats in the HF at 300 meters or so begining to occur with audio snake. I have not tested 300 meter Cat5e with analog for high fidelity
And not to this extent but amlnalog backup lines to delay clusters and a large scale festival as well as a bunch of speakers for events like an air show or speakers along a marathon route
Good demo! Back in the old days Ma Bell sent voice hundreds of miles over small gauge unshielded twisted pair. You could get special equalized dedicated lines for audio that would meet specs to FM radio.
Given the amount of inductance in those reels RF problem will be reduced some role off I can see . Nice demo The Schoeps shoot gun mikes where sensitive to coiling 300ft cap vs not coiled . This was at a telarc recording the cable does make a big effect on sound . This cable looks very fine .
With tightly twisted pairs like what Cat5e has, the coiling inductance of large diameter couls should be minimal. I think the dominant issue is capacitance and as the length increases, the capacitance is rolling off the HF and we see the phase shift on the smaart screen.
@@DaveRat The increased Capacitance will be harder to drive current and thus signal as it increases in a transmission line . Causing the impedance to change over it length since even though the cat5e is balanced the mic and micpre are not matched . What you see is the phase shift caused by the delay line you showed . I think it was a very good demo to show that in any real application Cat5e is a workable choose . Analog is effected in ways that simple transmission theory misses . This was a fine demo of what Heaviside work was in the 1890's . You are a fine teacher of some very advanced theory .
This is such great timing for me! I just ranover 500ft 8 channel snake cable, 350ft of speaker cable and 2000ft of cat5e cable for my studio. If 8 channel snake cable was a bit easier in the wallet, I would have ran a bit more. I never considered how well mic level could travel down cat5e; shocking really. Although, it being coiled as opposed to actually run at length may make a difference, but I ain't running 6 miles! Thanks Dave, always incredible information you share. Cheers!
Hiya Dave, love these interesting experiments you are doing! Years ago, I was involved with an outdoor recording experiment that involved some condenser mics placed about 600-700 meters away from the preamp. It was in a semi-rural environment, with a broadcast TV and radio antenna located about 4 km away. We had plastic conduit buried in the ground, and the first attempt at this involved using some Belden foil shielded install grade mic cable. The result was huge amounts of 60Hz noise on top of the mic signal. We tired a few different approaches, using preamps at the mic end and sending the signal much hotter(lower Z) back to the recording location, but that didn't improve the situation much. What did however work, was that we changed the mic cable from the foil shielded cable, to a star quad braided shield cable. Once we did that, the problem completely disappeared. We had four distinct mic lines, all doing the same thing that the original foil shielded cable. In hindsight, seeing you do this with much longer runs, had me thinking what really was the source of the problem we had. The only difference I see is that you have these cables coiled up, in a very small area, inside a building space. Our situation was outdoors with a straight 600 meter run. I suppose it's possible the Belden cable wasn't as twisted as it should have been, or how your Sound Tools cable is twisted. Seems to me, that as long as you have a very consistent twist and a decent preamp with good CMRR, the cable doesn't even need a shield. After all, the telephone company ran much longer twisted pair lines to carry very noiseless audio, much longer distances, without any shielding and worked this way for almost 100 years. That's the one thing we didn't try... using telephone cable. I suspect that you will be able to run your mic cable setup to a usable distance that will be dependent on the actual impedance of the copper connection. The more distance you add, the cable impedance will start to overtake the output impedance of the mic, and you will start to have a level drop as you already measured, like inserting a pad, but you still should be able to recover it with gain on your preamp, just a little more added ambient noise will also be there. I wouldn't hesitate to guess you could probably get 25 miles of cable, with still useable audio that would only need a little gain and EQ to fix. Thanks again for the experiments, they're awesome!
Thank you. As far as the 60hz, that was not from the radio antenna, more likely there was a wall current flowing through the shield somehow. As foil or braid over twisted wire should be pretty good at filtering out such a low frequency.
@@DaveRat That was my first thought when reading this, assuming sonicfrog is in the USA - here in the UK we'd expect a 50Hz hum. Over those distances there's a very good chance that currents circulating in the ground from the electricity network could cause a significant difference in potential between the mic and mixer. If any of the XLR shells are grounded or the mic chassis were grounded (I think this was more common in days gone by?) and in contact with general earth then it's easy to see how there could be a ground loop. Although it's weird that it went away with another (better quality) shielded cable.
Hi guys, thanks for the replies. It was in US(60Hz) and early 2000s time frame. We went through all kinds of things trying to figure out what was the source of the noise. We had condenser mics that needed phantom, and we tried even a small battery supply at the mics, coupled with some different line amplifiers, and using transformers with that original foil shielded install mic cable. There were lots of combinations of things tried to come to some solution. All of the attempts passed the audio, and allowed it to work, but there was such a strong 60Hz component there, it was unusable. Ground loop was the obvious first thought, but believe me that got rooted out on day one with the loads of experiments with power supplies, line amps and transformers. Our final thought was that the mic cable might just not be as twisted and uniform between the signal pairs as one would think. For say 50 meters maybe it was fine. But for the distance we had, it didn't work until we changed out the cable. So, the noise was actually in the signal lines, just not equally and hence, showed up as a nice 60Hz, from whatever was in the area inducing it. We had ourselves a 700m long guitar pickup with that original cable. :)
@@sonicfrog1 dare I ask what classified or unclassified project this was on, I mean for? I mean why would you did you need to go that far? I assume it was some sort of sensor monitoring type scenario. I recently went on a hike to an old Canal tunnel and thought it would be neat to put some microphones at both ends and make some noises and then realized I would need a third of a mile of cable which I don't have (yet). I still wanna try it although it'll probably be done with Wireless which is another distance question, how does it propagate underground how does it propagate in a tunnel....
Digital boards and audio over cat5 are the biggest game changers in the live audio field in my lifetime. Good timing too cause now I'm mid 50's and can't lug all the gear lol. Still have a 220 foot 32x8 splitter snake. It's heavier than I am! I don't think I've run my cat5 once without smiling thinking about how that beast of a snake is asleep in my basement hahaha. Amazing to see phantom work 6 miles away! I didn't expect that to work out. Great demo Dave. 👍
I've done a couple of things with 16 channel snakes and thought about other ways of doing it. When I built my own system out I decided on prioritizing portability and weight. I really do like the analog over CAT5 nature for simplicity and I pick myself up 4x 100ft foot cables which will probably be good for most of what I will ever do. Although I do have a idea for a multi CAT5e snake in my head using CAT5e 25 pair cable using AMP ends into a 6 Jack breakout at each end. That way the large ends can be removed for storage aiding the process of rolling the long 100-150ft cable up and shorter ( say 25' ) lengths can be substituted for smaller venues. I figure out of the 6 channels 3 channels would give me 12 channels of send and 1.5 channels would give me 6 channels of return, leaving a gigabit link open between stage and house and 2 pairs for maybe DMX. But it's just a crazy idea floating in my head, I wish somebody made a break out already, there is one from +studiohub that's more of a panel mount open design and I forget where it was they had a design lacking shielded connectors so no phantom power without modifications.
We (The rental side of Rat Sound) we're using multi Cat5e cables in an overall jacket but stopped doing so. A failure of on line kills the whole cable. We now user multiple Cat5e bundled and swap out lines if they get damaged. That way we have multiple lines than can be dicital or analog bundled with fiber as well
@@DaveRat I was wondering how the rental handle Booth -T- Stage, or if the cat system was just being used as breakouts on stage. Interesting so it was killing the whole cable more so than acting like a dead channel, hmmm. Yeah some way to bundle multiple individual line seems to be the way to go our big stuff like that. I was perusing the offerings and there aren't a lot of options for bundled CAT premade off the shelf. All I saw was 2 or 4 and assume anything past was custom.
It was not killing the whole car but carrying a 4xcat bundled cable with 1 dead cat line is not an option for use. 1 dead line means the cable is of no use to us
This channel, this video, this guy. Just gold. Great content, very interesting to see what happens at such high distances. I also loved your comparison x32 vs. M32 a lot ! Very in depth but never boring. Thanks for sharing your knowledge with us Dave!
definitely helps you visualize/appreciate what considerations those of us that design sports venues have when they jam the tv /radio folks up in the rafters of a 1.2 million square foot building.
I was being cocky about Cat-snakes (worried about audio quality using let's say 10m stage Cat-snakes, not 3 miles😁). Worries; XLR cabling (designed for audio fidelity for analog transfer), Ethernet cabling (designed for data integrity for digital transfer). Different cable specs for different applications. With Cat-snakes we are going to use cabling designed for transmission of digital signals for transmission of analogue signals. Without researching it, my technical brain said that it will negatively impact audio quality. You proved me wrong by showing it in practice! Brilliant! Thanks. I don't have to worry about using 10m Cat-snakes👍🏻🤟🏻😃
Good stuff and to be honest I knew it would work well but I did not realize that it would work that well better than mic cable and AES cable. I did other videos testing it as well as a 10 mi test
@@DaveRat yep :) its just ideal to show people that are not from the field of pro audio :) that expensive cables 1000$ and up (for one meter of cable having a line signal.....) are completely useless.. we already knew... but yeah
Especially the power cords after 50 miles of ac lines on cables and 75 feet or 12Gauge solid conductor wire in the house walls, some kbuclehead buys a $5000 IEC cable thinking it will make a difference. Makes me smile.
Cable rolls are collecting not only shunting capacitance C (depends on cable's quality and length - reducing upper frequencies), and serial resistance R (depends on cable's quality and length - reducing signal level), but serial inductance L too (depends on cable ROLLS summary serial inductance). This inductance is affecting passive dynamic mics (just voice coils, or voice coils + transformers like SM58); transformer output active electronics dynamic and condenser mics; playing games with shunting cable's capacitance. And the next input's impedance parameters are taking part in this game too, all it is rather complex...
@@DaveRat Thank you very much, your videos are so simple and so educating! Forgot to add - all the losses depend on the microphone's (or any other transducer's or gear's) output impedance. Lower impedance reduces affects depth. 8 ohms, or 50 ohms, or 600 ohms, or 10 kohms, etc., output impedances (passive or active) mean a serious difference in the signal loss in cables + other affects, including EMI/RFI noise and some phase shifting coming from LC components. But in the real life, we rarely have so long cables, so no reason for panic... :)
Interesting, I would have expected a significant drop in phantom power voltage. Thanks for testing! Would have been interesting to measure how much of the 48V is still getting through ;)
There will be a significant drop in voltage over even the 'shorter' 1.5 mile lengths, but it's dc and and most mics really don't need 48V except for some super high end stuff, like perhaps the Nuemann, but all that mean is its gonna lose some dynamic range and noise floor, hardly significant compared to the frequency rolloff's and cable induced noise at the lengths being talked about. Take away is... if you can put up with the sound degradation the phantom power can still fuel your condensers (unless you started with some crap deck that only sends out 12V and pretends that is good enough).
Even for a short cable the voltage can drop significantly from 48 Volts with a mic connected. That's because the phantom power standard is actually 48V fed onto pins 2 and 3 of the XLR through 6.8K resistors. So the resistance of the 6 miles of cable has a resistance far smaller than the resistors in the preamp feeding the power into the cable in the first place. It would be about 820 ohms added to the existing 6800, assuming 24 gauge copper mic cable. So the amount the voltage drops below 48V when the mic is connected would only be about 12% more with the 6 miles of cable than with a short cable. In reality this drops would be a bit more because I havent calculated the additional drop from the shield resistance, but its likely to be small compared to the twisted pairs. With one the Cat5e conductors serving as the GND wire rather than a proper shield, the drop would be more significant maybe closer to 35% more than without a long cable.
Hey Dave! Awesome demo! I love this type of direct comparison. Two SMALL points: 1) The base-line Frequency response of your mixer seems a bit outta wack (i.e. larger deviations from 0 dB Transfer function than one would expect), and I think the changes in the response would be CLEARER (and easier to quantify) with a smaller vertical scale on the transfer function. It looks like you have ~+24dB to -15dB, or an ~ 39dB range. This range could be reduced to +/- 15 dB making the changes easier to see (A vertical scale of +10dB to -20dB or -25dB might be best to show the roll-off at the longer lengths) THANK YOU for making these videos.... informative and FUN!!!! - Sam.
Hmm, well the electro magnetic waves travel about 60% the speed of light or 300,000 meters per sec. So 9600 meters divided by 300,000 equals . 032 or approximately 3 ms wire latency. That sounds like a fun test.
Great/interesting demo. The HF roll-off of the pink noise generator over extremely long cable lengths (causing increased inductance, resistance, capacitance) might be attributable to generator's output impedance. However, if the output of the pink noise generator is coupled directly from its opamps, and does not have any series resistance or capacitance, the long cable length roll-off might be negligible. If its output is transformer-coupled, then that would also introduce losses. (All of this applies to microphone impedances as well.) Thank you for such a great demo!!!
Yes! And this is why your test is so cool, for it deals with "real world" values, typically 150 ohms. In theory, as the source (mic, pink noise, etc.) impedance goes down, the effects of cable losses (resistance, capacitance) would go down as well. Soooo, this test reveals that the resistance of the cables affects volume, while the capacitance of the cables affects high frequencies. If the source impedances were reduced from, say, 150 ohms down to an ideal zero ohms, these cable lengths would have no effect at all. Thanks again, Dave, for such a great test! Your efforts are much appreciated!
@@DaveRat Dave, like your other viewers, I really appreciate this valuable testing you're doing...AND THEN...generously sharing it with all of us on UA-cam. I'm very grateful. Sure, theory is nice, but to see this stuff in action is so cool. As a studio tech, I've always been fascinated with the reasons "why" things sound the way they do. For instance, what makes a 414 and a U47 sound different, or an SSL and a Neve sound different, or a Marshall and a Fender sound different, etc. It reminds me of music. Yeah, it's great to understand the theory behind different musicians' styles but, hey, nothing compares with actually hearing it, right? (BTW, you also get into the "why" of things when you ask and answer important questions like "Why crowded shows sound dull...", etc., and that's really cool too.) One really important point you made during your testing is, despite any losses created with 6 miles of cable, you can then just reach up and tweak a tone control and get it all back again! Wow! Thanks again for everything you're doing.
Super interesting video! I've hooked up a measurement mic with 100m of cable before and compared it to the direct response, with negligible error. Cool to see that even 10x that distance doesn't have a huge effect! It might be worth noting that the error also depends on the input device's input impedance. Some ADCs have really low ii (
Is it the input impedance or the output 8mpedance of the mic that controls the overall line impedance? My understanding is that lower mic output impedance allows longer cable runs with less hf roll off
@@DaveRat I consulted with the guys on my Audio Discord and worked out a long answer: There are three main electrical properies of the cable, which cause signal degredation. These are the cable's resistance, capacitance and inductance. These three components form a passive circuit along with the two devices (mic and preamp), similar to a crossover circuit inside a passive speaker. tl;dr: High preamp input impedance reduces overall signal loss Low mic output impedance reduces HF roll-off Thicker cable=less overall loss, but more HF loss, relatively speaking Long version: Let's talk about resistance first, since that's easy: First of all, we can say that at analog audio frequencies, cable resistance is the same for all frequencies (no need for silver plated audiophile snake oil). The mic's impedance is small compared to the preamp's, so it has almost no effect here (similar to damping factor in amps). The cable resistance causes a flat loss at all frequencies. Looking at the lowest frequencies in your 6 mile test, we see a loss of about 7dB, which plugged into a calculator looks like the wire is 27AWG. The Xenyx's input impedance is 2.6kΩ. The X32's input impedance for example is 5kΩ, so you'd see a 4dB reduction instead, compared to the 7dB on the Xenyx. Time to talk about cable capacitance: This is what causes the HF roll-off. It's basically a parallel capacitor, which is a 1st order LPF. Preamp input impedance has close to no effect on this, it is indeed the source device's output impedance, like you said. The Xenyx's is 240Ω, which I what we see in SMAART, I suppose? You can generalize, that a device with half the output impedance will roughtly have half the HF loss. SM58 is 150Ω, which would be better than the Xenyx already. KM184 is 50Ω, which would reduce that HF loss to only about a fifth, for example. Now comes the wierd part, we don't really have to worry about, inductance: This depends on cable layout. We know having a power cable on a drum/coiled up heats it up quickly because it's a)bunched up and can't transfer its heat to its surroundings well and b)a coil is an inductor, which forms a magnetic field. Since you're sending a differential (symmetric) signal through twisted pairs of cable, the two magnetic fields cancel each other out and not much is happening. If that signal was an unbalanced signal however, you'd have a series inductor in the loop, which forms a 2nd order LPF with the cable capacitance, making HF loss even worse. By how much I don't know, someone would have to test that. Note that this is mostly an issue when the cable is still on the drums and you (probably?) won't have to worry about it when it's laid out in a straight line. Of course, sending an unbalanced signal through miles of cables will cause a lot of other issues, but that's what we have DI boxes for. And for the cable properties: A thicker cable will have a lower resistance, but higher capacitance. This means lower loss overall, but more HF-loss.
Phantom power is very similar the voltage present on a copper telephone line. The same thing happens to telco lines the farther you go out the more attenuation in the high end but in the telco world we employ what is called a passive load coil that helps to make up for the loss. Since you are using what is essentially telephone wire to run this test I'm not sure if the cables coiled up are effectively acting like a load coil and affecting your results positively or not. You could try to unroll them and repeat the test and place one roll up cable reel in the middle switching it in and out to verify weather or not it effects your high end.
Hmmm, comparing the impact of coiling of high bandwidth precision twisted pair Cat5e to telephone line may not be fully on point Are you sure the twisted pairs of Cat5e would be impacted by coiling the same as telephone line? Anyway, the test was to see how far audio and phantom would go down Cat5e and it well exceeded expectations. So you think that if I uncoil it will go even farther than what is already too far for nearly all applications?
@@DaveRat You are correct they are not exactly the same telco twisted copper is is generally Cat3. I was just curious if there was any effect having them all coiled up.
My understanding is that perfectly twisted pairs should be immune to coiling inductance. That said, nothing is perfect. And I am not curious enough to uncoil 6 miles of cable and find out. At least not yet
@@DaveRat Yes I agree don't do that, make an intern or someone do it. LOL. just kidding. Love the channel by the way keep it up. en.wikipedia.org/wiki/Loading_coil
Might want to talk with old radio engineers that used telephone dry lines that are cat3 for miles for broadcast feeds or studio to transmitter links. Yes, they had to have a device at the end to compensate for EQ.
Very cool. Yeah I was getting questions asking how far they can run analog down the Cat5e cable I designed. Mainly looking at the 500 to 1000 meter lengths. But one customer wanted longer as well. Well this was to show that down a mile or so without any additional stuff, it will work fairly well just plug and play
Thanks for this. No idea why but i just had this weird assumption that too long of a cable would cause a crazy delay. You've obviously debunked that for me so thank you!
With regards to speed of signal transmission: the speed of Electromagnetic signals running through a copper cable is approx. 200,000 km / second. Very fast indeed! Meaning that you would need to have 200,000 km of cable in order to introduce a delay of one (1) second. That’s a lot of cable. A typical single pair mike cable weighs 65g/meter. 200,000 km of cable would weigh 13,000 tons (13,000,000 kg). As said above: that’s a lot of cable!
Dave, it would be very interesting to see this test with a digital console sending a high amount of tracks down the different distances to see if there's any digital degradation once you start adding tracks. If I had that much cable I would try it myself...
Next try different consoles? See if different consoles can push 48v that far. Would also be interesting to measure heat on that pre circuit. Would also be interesting to see how much resistance was in that lenght of cable. As always ty Dave!
My understanding is usually that couplers is where you usually lose your most power (especially with stranded, so check your 5e. Solid is more annoying to terminate, but would be better for insertion loss), so I'd be interested to see if you could push it further with just a longer cable instead of multiple connected spools.
I think that couplers do have an impact on data frequencies of 100k, 1 meg or higher, but this is analog over cat5. So the relative simple 20 to 20k is a lot more resilient and not impacted much.
Very interesting demo would it be possible for you to make a vid on how foh desks are switched in and out at festivals for all the guest engineers that would be a great help for me thank you I love your videos ❤️
That is one hell of a lot of inductor coils! I wish you would had measured the total resistance of 6 miles of wire. And also the inductance. Curious to know that.
Interesting! I use a program called ShareX to record screens to video, it will also record the laptop sound making it easy to align the clips in the editor. This allows me to avoid pointing a camera at the screen .
Well we’ll well! Hahaha. This is even more Brilliant!!! Wonder what a cloudlifter or a line driver on one end “pushing” the audio rather than pulling the audio. Just thinking if you would actually need this for simple monitoring this is great. Not for recording for any Grammy awards but hey. I bet someone would buy it. LOL.
Do coils create inductors when the wires are tightly twisted pairs? Or does tightly twisting the wires cancel out the electro magnetic radiation needed for inductance to occur?
@@DaveRat You're absolutely right, these twisted pairs cancel the magnetic fields out so it doesn't matter whether the cable is rolled up or not. What does happen, however, is that INSIDE the cable itself, the insulation between your conductors and the shielding create a small capacitence, and the cable itself acts as a small inductor. In RF engineeing we call this a transmission line. This acts as a low pass filter and therefore can limit the bandwidth of your signal. The higher the frequency or the longer the cable, the higher the losses, hence you lack your highs at the end of the line! This is also where the phaseshift comes from, regarding the distance is still really short taking the speed a signal travels through a wire in mind. This is why RF cable in the GHz range is so incredibly expensive, the centre insulator has to be flexible yet have a very low dielectric constant.
There is some really early & interesting science on pumping _analog_ audio long distances. The focus was on extending telephone lines _before_ the invention of the triode vacuum tube. Three really inventive folks came up with versions of the "loading coil". ¶ If curious about this, please see Wikipedia for...: #1 Oliver Heaviside #2 George Campbell #3 Michael Pupin === AT&T bought Pupin's patent to stay out of legal battle, making him a very wealthy man. A physics professor at Columbia, the Department's building is named after him. A fascinating person, he was an inventor in several area and Edwin Armstrong was his student. _..._ /Mike
Great stuff and my goal was to see how the gear we have readily available to us responds to using it for long runs. Taking all the theory and ideas based on gear we don't have and seeing how the gear we do have works!
A coaxial cable would theoretically be the perfect fit for this. That white stuff around the wire is there to make sure there's always a constant charge that stays the same whether it's one meter long or one kilometer
No it would not... The miracle of cat5/6 is the incredible well balanced (and different) twist density on each pair. If you tried to do this on unbalanced co-ax you would hear nothing but two cities worth of hum before the mic signal hit your preamps.
Coax does deal with high frequencies well as it has less capacitance but but the twisted pairs are better at rejecting noise. But the test was to see how far phantom power would work and with coax, that would be easy, 0 feet.
Though the series resistance will be 500 ohms, phantom current is quite low, maybe 20mA at the highest, so voltage drop should be 10v max. Many, but not all, 48v microphones would be ok with this.
Cat5/6 has an inherent characteristic impedance of 110ohms - so it will handle 50 to 200 fairly well. You'll get some worse frequency rolloff on a 600ohm mic... and trying this with a guitar pickup... well, just lets not :)
Hey dave , another classic vid , obviously u wud,nt run those cables spooled but but for instance if they were layed out how do they deal w/ heat dispersion, a mile though, absolutely amazing ,...
Did you measure the voltage drop, I believe the phantom mics are specified 18-48V. Video idea, at what voltage will phantom mics not work. Nice video, thanks!
I am actually really impressed by the fact that anything even remotly related to the original signal would come out of a cablerun like that! However i see a slight potential "issue" with the testing of the phantom power as i asume either the XLR splitter, the XLR switcher or maybe both have the grounds of all connectors bridged. What that would mean is that the sheild of the long cable would be in parallel to the sheild of the short cable run, almost eliminating the impact of it's electrical resistance. In terms of signal strength there shouldn't be much of a difference with a balanced signal, however i do think that the impact on phantom power and maybe also sensitivity to EMI could be affected by this test setup. Either way, this was a great video and an impressive test regardless.
Yes, on one hand the ground length is 25% of the miles but also the ground braid is much thicker than the twisted pairs and has a lower resistance. So phantom travels at least 6 miles down twisted pairs of the 12 total it would travel, but the 6 miles of ground that it is not travelling is low resistance So maybe the real world equiv of phantom down 4 miles or so
I've been in large recording studio complexes with several studios where the audio from say, studio c's live room would get patched to studio a's control room, and the total signal path could be hundreds or even thousands of feet.
The idea for this video came from a customer buying Cat5e cable to put speakers up for a 1/2 marathon route 8n an area without cell service or WiFi The question was "how far can I run analog over Cat5e? So I tested it and made a vid. The 1/2 marathon had the drive unit in the middle. So 6 miles each way would do it and with shorter runs because there was a generator and the ability to refresh the signal at each speaker area evenly spaced on the route.
My prediction before watching. 48V will work fine, the resistance of the cable won't be that significant in comparison to the 6.8K resistors the phantom is already being supplied via, though it will add some capacitance. The 48V should drop when it sees the uncharged capacitance, then come back up again as it charges, and work fine from then on out.
A ton of cheap audio gear will put out more like 12-24v on phantom. It's amazing the number of preamps that tolerate it. I do have a few that want the full +48v however. Test first!
Dave you make very cool videos and I have learned a lot from you. I have a question concerning this video. Did you consider the fact that coiled cable reels may create millihenry choke coils which will inherently create a low pass filter in your experiment?
Great video! I wonder how much of that roll off is due to the wires being coiled. They are acting like air core inductors. What would the difference be if the wire was straight vs coiled?
Wonder what the voltage drop is. I know most condenser mics will run in 12v even when the spec is +48v, but I have a couple that are more sensitive to voltage. Also be aware, that much wire will delay the signal a bit. Old osciliscopes used to use long coils of wire exaclty for that. Not enough to hear, but phase issues can arise. Have you done this with a dynamic lol? Now i just need to wire my house in cat5 and add preamps to every room. :D
Hmmm, math calcs. As far as delay, since sound travels about 200,000,000 meters per second in wire, the delay would be around .05 ms or about the equivalent of 1/2". In other words, the delay in the wire is less than moving the mic an inch further from lips As far as the voltage drop, that is an easy calc as well, Look up the resistance per 1000ft of 26ga wire, divide by 2, as there is 2 wires, then double it as it travels there and back. Then look up the current draw of the mic. Then apply ohms law. I believe I did the calc in another comment here on the vid got don't recall the result, I think it was less than a 12 volt drop. But the cald will get ya close
The disapation of a 48volt phantom power microphone feed starts to deteriorate over the longer the distance! The expectations are typical from what we would expect on the principles of Ohm's Law! This is because for every 2 and a half centremetres within..say 12,800 metres (12 miles) before the signal enters three thirds below it's roll off threshold that it then becomes more apparent say around -128bB give or take! It's only then that it starts to lose it's basic functionality such as it's power conductivity, impedance strength which is long before an acoustic delay becomes audibly noticeable! The longer the length of cable from it's source then the more of the odd popping noises and on many of occasions RFI (radio frequency interference) despite the cable being rf suppressed at the mixer or limiter/compressor point! Although upstandably the signal will be considerably weaker which will need to be amplified due to the increase in noise static! Another important factor that one may forget to take into consideration is the quality of the phantom power microphone cable for each drum reel regarding it's outer and inner sleeving and outer insulation! The transmission of live acoustic electrical signals during that of a live festival, concert is no stranger to acoustic hiccups whether it's cable cracks, phantom pops, rf interference, hum issues etc Using a Behringer feedback destroyer for ie resolves many PA problems but not all of them although the principles of cleaning up the signal are more or less the same aswell as the rate of acoustic feedback! So in summary it's really just an experiment to see how far up a professional graded XLR microphone cable takes before a delay becomes audibly noticeable! Technically, long after the signal becomes hardly audible from it's source!
@@DaveRat It really is absolutely fascinating Dave for you to actually put these live acoustic experiments to the test in order to ascertain whether there is some technical and mathematical truth to them thus debunking or confirming some of the sound industry's greatest myths! We can just imagine a very young Alexander Graham Bell conducting similar experiments with microphone's before the concept of the telephone arrived (back in 1876 I think) only for it to be improved much time later with a more efficient carbon telephone transmitter by the late Thomas Edison! 🙂👍
He llo Sono!! Interesting. Yes etherc9m couplers do cause 8ssues for cat5s running data as the frequency is very high. For analog over cat5e. Those ethercon couplers actually have much thicker wire than the Cat5e cable so they should have minimal impact. I believe the main causes of the drops are resistance from the long thin wire and capacitance from two wires that are very long being next to each other 8n the twisted pair
Any connection will slightly degrade the signal, high speed data is especially impacted like 100k, 1 meg or above. Analog audio is like 20k so it's a very low frequency and lower frequencies are less impacted. There are 2 versions of neuteik barrel as well. One is way better for data than the other. For analog it makes no real difference which one.
I have no idea what any of this means except the fact that you can get a fairly clear signal that far without boosters or repeaters whatever they are called. Also, what is phantom power and what is it doing in this situation.
Please test and compare it to 100 x 100m mic leads all connected sequentially. And also 10,000m of Monster cable. And 10,000m of unrolled cable. LOL! What if it was unbalanced - does it pickup AM radio? Can you use an EQ to restore and flatten it out? The 48v Phantom should go for several km because that's what old analog PSTN phones ran from sent from the telephone exchange.
What can be interresting, when you plug mic to 1input, and try to draw gignal from remaining chanel lines in Cat cable. How strong crosstalk analog induction in cat cables is, when working balanced/unbalanced.
I work at a high school and use Wall-Cats all over the place. The district is much better at installing Cat cable rather than multiple mic lines. My question is can you run DMX and audio over the same Cat line?
Cool video, that high end was really dull by the end but what a testament to the distances one can achieve, so interesting the phantom power held out. :)
That was 17 minutes well spent. Frequency response and level aside, I cant help but wonder about noise rejection and interference in a less friendly environment. That might be a more limiting factor.
Yes, those are concerns, yet the applications that long analog cable runs are most likely going to be used has a high probability of being in remote locations without wifi or cell signal and possibly dependant on power generators. So interference would be less likely.
Well. The pink was not line level but it was a low impedance output. So what you see on smaart with pink is what line level will do and what you hear is what mics will do
Hi Dave. Two questions. 1: How on earth did you come up with this challenge? 2: You have now concluded that it is possible to run an analog microphone signal through several miles of cable with only a minor impact to the quality of the signal. But do you know why that is?
Well, before there was digital and fiber, analog was run everywhere. I believe analog was designed to run long distances. Older designed mics like the RE20 have selectable impedances going down to 50 ohms That should allow it to run 2x to 3x farther with the same HF rolloff vs the 150 or 200 it is set to when sold.
I always wondered about this. I use a 100ft. 16 channel snake from my control room to my live room. I wondered if it made a difference going through that extra 100ft. Cable. The answer is no. At least I can't tell the difference. Not long enough.
This was not a test of maximum fidelity, just a test of function. I would say that 100 feet will make a slight difference that with low impedance sources would be inaudible but measurable. Shorter wires are better but the difference is very small
@@DaveRat Wow, Yeah. I can't tell the difference. I'm sure on one of those computer frequency meters there would be a slight difference. I can't believe that you did sound for Soundgarden. Chris Cornell was one of my favorite musicians. It's a shame what happened to him. I was blown away. I've met a lot of big time musicians being in a touring band but never got to meet him unfortunately. Great Vocalist.
I wonder what would happen if that cable wasn't coiled in a small space, but in a straight line round trip, I think there would probably be a lot more interference
Hmmm, the customer that bought our Soundtools Supercat cable to run signal to speakers along a sporting event route said it still works great with no issues
A fellow senior grumpy engineer friend of mine who's too pretentious to bother commenting here himself because of fear of "noob relation" mentioned: "Interesting test with the cable runs. I'm surprised that no one mentioned that the cables are in coils which will produce impedance even though the cables are shielded. The common practice with extra lengths when running cables, is to lay it out in a figure 8 to avoid the problem."
Hmmm, I think there is some misunderstanding of shielded vs twisted pair. Twisted pair is inductance cancelling, Shielded is not. Either way, if indeed the coils were to create issues, then we could go even longer, but I ran out of cables to use and the whole purpose of the test was to see how far phantom would power a mic. Is your friend saying that uncoiling would achieve my goal of phantom not powering the mic?
@@DaveRat he made no mention of phantom power being lost over that distance. I think he was just grumpy to see the coils and overlooked the mention of it being twisted pairs. Cheers for your quick reply Dave! Long live coffee cat :3
Ha and awesome! Yeah, people like to spot things and spit out info as if they know what they are talking about. Best thing to do is ask him for ducumentaion and a video of the testing he did to gain that knowledge.
@@DaveRat I think your education is more valid as you are far more relevant compared to an old grump who hasn't had a gig in two decades (nor embraced the digital era for that matter), I doubt running audio over twisted pairs is a concept he's even familiar with. If we're to do a similar installation but not use your specific branded cable, as long as we're using Cat 5e twisted, we should be fine for most installations (say for tie-lines in a studio where the runs would be no more than a few hundred meters?). I'm trying to help another peer of mine design and build a new studio space but classic analog cabling (mogami or the sort) gets pricey. I suggested some cat boxes and running the audio over twisted pair instead. Also does Sound Tools provide any solutions for the wall box that is more than 8 channels? Could we present a custom design and have that built out? say for 24 ch or more? Thanks for sharing your knowledge with us freely and publicly :-)
I'm surprised nobody realized that as soon as the signal was sent back up the cat5 again (looped through multiple pairs) the gnd return path (shield) was eliminated from the circuit since all the pairs share the shield down the cable and back! This cuts the overall length of cable the phantom power is using in 1/2, 1/3, or 1/4 (depending on how many pairs your looking in and out of), and cuts down in the amount of voltage loss at the condenser. It invalidates the question of how long can you run phantom power because only the +v is running the distance (and shared on 2 conductors, as is the nature of phantom power). To keep the test real you can't look back down multiple pairs, sorry! Still an interesting test though.
Great observation! The ground does not carry any signal on balanced lines and all the signal travels down tristed pairs. So sound quality should not be impacted for better or worse But yes, the doubling back does decrease the resistive losses to phantom power. Though with the supercat, the braid shield has so much copper, the resistive losses are minimal in comparison to the losses of the twisted pair wires so not doubling back should still be about the same. With supercat sound, the pairs are individually sheilded and the doubling back would reduce some losses to phantom voltage Very cool!
@@DaveRat I disagree, regarding the supercat sound cable and individual shields... All those shields come together to a common connector shell at both ends, so if your running the distance (and not looping back) then you will benefit from the less resistances of all 4 coppers sharing the load; but if you loop the signal back then, just like with the other cables in the test, you eliminate the shield length completely from the active DC circuit powering the microphone! Also, with runs that long, even with "thick shield" I wouldn't discount the voltage loss from the shield over miles of cable. The end result, though, as pointed out earlier, will likely be somewhere in the range of 10-15 volts of drop (depending of course on how much current the mic is pulling) which should have little to no effect on the most microphones if your source is 48v (I'm not doing the calculation myself just trusting the calculation I read earlier).
The super cat sound with individual wires would be lower resistance doubling back correct not disagreeing with that. Say we had best case scenario and the shield resistance was eliminated completely that would reduce 1/2 of the total resistance the signal sees or a 6 DB difference. But half of the cable has super thick grounds so the difference will be less maybe three or four DB differential between doubling back and not
@@DaveRat I think you misunderstood my point... There will be no loss of "signal" due to anything regarding the shield, because signal does not pass through the shield. The point I was making is that regardless of which cable/shield type you are using, once you send the signal "back down" the pipe on another pair and pick it up at the end where you started, you have now effectively eliminated the shield (your best case scenario in real life!) from the active circuit powering the microphone! Even with the individuals shields, they all bond together at the Ethernet connector shell, and that is the only part of the cable that carries the - leg of current to the microphone! You won't lose db's off your signal but you will not be presenting the correct amount of voltage loss that a cable 2-4x the distance of the actual Ethernet cable jacket is. Again, even with the shield as part of the circuit, it's probably not enough loss to shut down most mics if you have a solid 48v supply at the input end; but even with a "thick shield" it will add a measurable amount of resistance / voltage loss to the circuit, if it wasn't being bypassed by the loop back to the beginning in the cable. Either way, your no longer accurately measuring the correct voltage loss after that first 1.5 mile run, when you looped the signal back through different pairs.
your network cables act as a henry coil allowing for amplification when spooled even knowing cables are shielded .... you would have to unroll the cabling in order to get a better controlled test so you do not have the amplification from the spooled coils of wire, suggestion unrolling the coils into full lenth back and forth 100 meters at a time ... much less chance of amplification then the rolled coil even if cables are shielded.
best way to go long distances is xlr output from the board to a transceiver hub with xlr input/output and outputs to fiber cable, you can go up to 180 miles without any loss or a booster then the same on the other end, this fiber cable you can leave spooled because it does not carry a value for a henry coil when spooled no copper or any other combinations of metals incorporated into the cable ....this I can guarantee. if they would incorporate fiber cables into digital boards with remote stage boxes like the X32 you would not have to worry about electric issues at the main board and can use a separate power source all together even out of phase, it would not cause a problem, it would still be IO but by light instead of electric signals in the cable.
Hmmm, I am testing the worst case. Also, tightly twisted pairs tend not to have much inductance. If this was non twisted speaker cable, I would agree that there could be issues from coiling. Anyway, I want the issues as I was trying to see how long the cable would be for the phantom mic to stop working We get customers asking how long they can run analog down the Cat5e cables we manufacture, so Ihad some fun doing a test. And doing the test with the cable coiled means I can save from telling them, yeah. You need to spool all the wire into a big mess for it to work. Yuck. For the touring and festival systems we supply, we can spit out fiber, Cat5e or analog to a multitude of locations. And also it's important to remember that making things complex is not always better. One application for long cable runs was for a 1/2 marathon announce mic and music with battery powered speakers along the route every 600 meters or so. No wifi, no cell service area and fidelity is not a big deal. Do ya use fiber and network and digital or just run some copper and be done? How long can the copper be? What will it sound like? Those are the questions I was seeking to answer.
@@DaveRat I totally get ya, its definitely a cool video, I liked how you could see the roll off but not until over a mile in on the scope great visual perspective, I think cat5e is so much better then the old school snakes and can still be used as analog with your connectors thanks for getting back to me, I appreciate your videos. I am curious if you would be open to a vid with cat5e and a wireless transceiver set with encryption ?.. would you even consider a wireless transceiver set to send sound to stage ?
Hmmm, I don't really do vids on stuff that I am not pretty familiar with on some level. As far as using wireless for transmitting to stage, as with everything, avoid complexity and avoid adding anything that can fail unless it brings district advantages. Perhaps in a pinch but wireless frequencies are extremely scarce and we pretty much need power everywhere and running fiber with the power gets us signal everywhere
Cool and also maybe check out Soundtools.com catbox, cat tails,, wallcat, and cat rack for aluminum ones that won't rust or have the paint chip. Plus Soundtools has much nicer tails and versions no one else makes like the supercat tails
I could think of some situations where running super inexpensive sheilded Cat5e may be a more reliable, less expensive or less complex solution to other methods. Bike race with announce speakers along the route in a remote location may want to weigh costs and complexities of setting up wireless transmission vs just running copper. Also, in making soundtools analog over cat5e I am faclscinated to learn how much of the world still embraces analog over digital solutions for infrastructure. Hospitals and building being wired with our Wall at boxes and super long cable runs and routing to multiple buildings. As useful and fun as digital and wireless may be, running a copper wire is still a great solution for many applications
@@DaveRat When I was in the Navy I worked with deep submersibles, tethered UAV's. The most expensive part was the tether. It carried power and comms etc. Wired is always prefered. However not sure about miles of it hahahaha! And it, as you say, just works...
Hello Dave I totally understand however rather to do anything I think it would be interesting to nevertheless have a credits in order to start from a base and it is up to me to consider your professional advice
This is helpful for when you need to run sound on the space station.
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There's no resistance in space. 🤡
To motion yes, no air but electrons in wire have no concept of gravity or wind
@@ThePlagueGameing O think i saw some resistance at Star wars movie
If you're referring to the ISS, it's only a little over 100 meters
The impressive thing is that the audio travelling through 9600 meters of cable has the evquivalent delay of around one centimeter through air!
Assuming your FOH is at the end of the line, you‘d have the signal 28 seconds earlier on the console than your hear it. Not the best for tapping delays I guess…
Great stuff! And love the math and perspective
@@DaveRat That's a whole lot of time to bleep out some expletives... or even just... you guys totally suck, I'ma just cue up an mp3 (or even go find a cd) here, eat an ice cream, and play that... before anyone else hears how bad you (they) are live :)
Except you wouldn't hear much at all at 9600m from the speaker (even the curvature of the earth will affect your coverage ;)
What about if you mic'ed and realtime broadcasted the center of a thunderstorm or a war.
Seems nearby people six miles away may hear the broadcast and then the delayed acoustic sound
Okay, but can you calculate the time it would take between me adjusting the EQ and me realising that the EQ was bypassed the entire time?
I did an entire event off of these cable runs, had to run two relay towers two football fields away. You saved me thousands in cable costs
That's makes my day!!! And exactly why I do these videos!
That is a really cool demo. I've never used a mic cable more than about 150 feet in total (snake + mic cable proper). Back in the mid-70's when I was being taught about pro audio, I was told that normal balanced low-z mic lines could be up to 1,000 feet with no ill effects, and if you wanted to go further, there were a lot of mics that could be switched to a really low source impedance (50 ohms, usually) and these could drive a mile of cable. Looks like the engineers who designed the system way back in the day knew their way around a slide rule!
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Back in ‘94 I helped install 8 or 10 12 pair audio mults for an NFL playoff game telecast, the runs were about 1,000 feet from tv trucks to the stage inside the stadium. We also had 10 coax video feeds plus 8 triax camera cables. Today we would run a single tac12 bundle and have spare fibers. The audio guys never whined that I recall. They had to run mics from the stage back, RTS intercom & IFB’s back to the stage from the trucks.
I think this shows that for low and mid fidelity runs, long cables work for signal level. For high fidelity, I have done tests that show there are audible errticats in the HF at 300 meters or so begining to occur with audio snake. I have not tested 300 meter Cat5e with analog for high fidelity
I love these videos please keep 'em coming! thanks!!
Awesome will do!
That is a really cool demo. Never thought about what would happen cable runs of such extraordinary length.
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analog phone lines..
And not to this extent but amlnalog backup lines to delay clusters and a large scale festival as well as a bunch of speakers for events like an air show or speakers along a marathon route
Good demo! Back in the old days Ma Bell sent voice hundreds of miles over small gauge unshielded twisted pair. You could get special equalized dedicated lines for audio that would meet specs to FM radio.
Very cool, yes, with added electronics we coul go much farther.
Great demo Dave. Love watching these technical audio experiments
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This is great! In our next concert I will stay 1 mile away from our guitarist and the public won‘t notice a difference
The lighting and vid crew may have chleges though the sound humans have ya sorted
Given the amount of inductance in those reels RF problem will be reduced some role off I can see . Nice demo The Schoeps shoot gun mikes where sensitive to coiling 300ft cap vs not coiled . This was at a telarc recording the cable does make a big effect on sound . This cable looks very fine .
With tightly twisted pairs like what Cat5e has, the coiling inductance of large diameter couls should be minimal. I think the dominant issue is capacitance and as the length increases, the capacitance is rolling off the HF and we see the phase shift on the smaart screen.
@@DaveRat The increased Capacitance will be harder to drive current and thus signal as it increases in a transmission line . Causing the impedance to change over it length since even though the cat5e is balanced the mic and micpre are not matched . What you see is the phase shift caused by the delay line you showed . I think it was a very good demo to show that in any real application Cat5e is a workable choose . Analog is effected in ways that simple transmission theory misses . This was a fine demo of what Heaviside work was in the 1890's . You are a fine teacher of some very advanced theory .
Fun and thank you!!
This is such great timing for me! I just ranover 500ft 8 channel snake cable, 350ft of speaker cable and 2000ft of cat5e cable for my studio. If 8 channel snake cable was a bit easier in the wallet, I would have ran a bit more. I never considered how well mic level could travel down cat5e; shocking really. Although, it being coiled as opposed to actually run at length may make a difference, but I ain't running 6 miles!
Thanks Dave, always incredible information you share.
Cheers!
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Hiya Dave, love these interesting experiments you are doing! Years ago, I was involved with an outdoor recording experiment that involved some condenser mics placed about 600-700 meters away from the preamp. It was in a semi-rural environment, with a broadcast TV and radio antenna located about 4 km away. We had plastic conduit buried in the ground, and the first attempt at this involved using some Belden foil shielded install grade mic cable. The result was huge amounts of 60Hz noise on top of the mic signal. We tired a few different approaches, using preamps at the mic end and sending the signal much hotter(lower Z) back to the recording location, but that didn't improve the situation much. What did however work, was that we changed the mic cable from the foil shielded cable, to a star quad braided shield cable. Once we did that, the problem completely disappeared. We had four distinct mic lines, all doing the same thing that the original foil shielded cable. In hindsight, seeing you do this with much longer runs, had me thinking what really was the source of the problem we had. The only difference I see is that you have these cables coiled up, in a very small area, inside a building space. Our situation was outdoors with a straight 600 meter run. I suppose it's possible the Belden cable wasn't as twisted as it should have been, or how your Sound Tools cable is twisted. Seems to me, that as long as you have a very consistent twist and a decent preamp with good CMRR, the cable doesn't even need a shield. After all, the telephone company ran much longer twisted pair lines to carry very noiseless audio, much longer distances, without any shielding and worked this way for almost 100 years. That's the one thing we didn't try... using telephone cable. I suspect that you will be able to run your mic cable setup to a usable distance that will be dependent on the actual impedance of the copper connection. The more distance you add, the cable impedance will start to overtake the output impedance of the mic, and you will start to have a level drop as you already measured, like inserting a pad, but you still should be able to recover it with gain on your preamp, just a little more added ambient noise will also be there. I wouldn't hesitate to guess you could probably get 25 miles of cable, with still useable audio that would only need a little gain and EQ to fix. Thanks again for the experiments, they're awesome!
Thank you. As far as the 60hz, that was not from the radio antenna, more likely there was a wall current flowing through the shield somehow. As foil or braid over twisted wire should be pretty good at filtering out such a low frequency.
@@DaveRat That was my first thought when reading this, assuming sonicfrog is in the USA - here in the UK we'd expect a 50Hz hum. Over those distances there's a very good chance that currents circulating in the ground from the electricity network could cause a significant difference in potential between the mic and mixer. If any of the XLR shells are grounded or the mic chassis were grounded (I think this was more common in days gone by?) and in contact with general earth then it's easy to see how there could be a ground loop. Although it's weird that it went away with another (better quality) shielded cable.
Agreed
Hi guys, thanks for the replies. It was in US(60Hz) and early 2000s time frame. We went through all kinds of things trying to figure out what was the source of the noise. We had condenser mics that needed phantom, and we tried even a small battery supply at the mics, coupled with some different line amplifiers, and using transformers with that original foil shielded install mic cable. There were lots of combinations of things tried to come to some solution. All of the attempts passed the audio, and allowed it to work, but there was such a strong 60Hz component there, it was unusable. Ground loop was the obvious first thought, but believe me that got rooted out on day one with the loads of experiments with power supplies, line amps and transformers. Our final thought was that the mic cable might just not be as twisted and uniform between the signal pairs as one would think. For say 50 meters maybe it was fine. But for the distance we had, it didn't work until we changed out the cable. So, the noise was actually in the signal lines, just not equally and hence, showed up as a nice 60Hz, from whatever was in the area inducing it. We had ourselves a 700m long guitar pickup with that original cable. :)
@@sonicfrog1 dare I ask what classified or unclassified project this was on, I mean for? I mean why would you did you need to go that far? I assume it was some sort of sensor monitoring type scenario.
I recently went on a hike to an old Canal tunnel and thought it would be neat to put some microphones at both ends and make some noises and then realized I would need a third of a mile of cable which I don't have (yet). I still wanna try it although it'll probably be done with Wireless which is another distance question, how does it propagate underground how does it propagate in a tunnel....
👍real professional! That's what I call one clear experimental demonstration, well done!! 👏👏👏
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Awesome experiment man!! Love the warehouse too!!
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Love your experimental videos Dave, the chilli peppers could a gig from their living rooms and just move the P.A's from town to town haha 😄
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Don't give them ideas bro. lmao
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This is one of the coolest things I have ever seen, thank you Dave!
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Digital boards and audio over cat5 are the biggest game changers in the live audio field in my lifetime. Good timing too cause now I'm mid 50's and can't lug all the gear lol. Still have a 220 foot 32x8 splitter snake. It's heavier than I am! I don't think I've run my cat5 once without smiling thinking about how that beast of a snake is asleep in my basement hahaha. Amazing to see phantom work 6 miles away! I didn't expect that to work out. Great demo Dave. 👍
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I've done a couple of things with 16 channel snakes and thought about other ways of doing it. When I built my own system out I decided on prioritizing portability and weight. I really do like the analog over CAT5 nature for simplicity and I pick myself up 4x 100ft foot cables which will probably be good for most of what I will ever do. Although I do have a idea for a multi CAT5e snake in my head using CAT5e 25 pair cable using AMP ends into a 6 Jack breakout at each end. That way the large ends can be removed for storage aiding the process of rolling the long 100-150ft cable up and shorter ( say 25' ) lengths can be substituted for smaller venues. I figure out of the 6 channels 3 channels would give me 12 channels of send and 1.5 channels would give me 6 channels of return, leaving a gigabit link open between stage and house and 2 pairs for maybe DMX. But it's just a crazy idea floating in my head, I wish somebody made a break out already, there is one from +studiohub that's more of a panel mount open design and I forget where it was they had a design lacking shielded connectors so no phantom power without modifications.
We (The rental side of Rat Sound) we're using multi Cat5e cables in an overall jacket but stopped doing so.
A failure of on line kills the whole cable. We now user multiple Cat5e bundled and swap out lines if they get damaged. That way we have multiple lines than can be dicital or analog bundled with fiber as well
@@DaveRat I was wondering how the rental handle Booth -T- Stage, or if the cat system was just being used as breakouts on stage.
Interesting so it was killing the whole cable more so than acting like a dead channel, hmmm. Yeah some way to bundle multiple individual line seems to be the way to go our big stuff like that. I was perusing the offerings and there aren't a lot of options for bundled CAT premade off the shelf. All I saw was 2 or 4 and assume anything past was custom.
It was not killing the whole car but carrying a 4xcat bundled cable with 1 dead cat line is not an option for use. 1 dead line means the cable is of no use to us
This channel, this video, this guy. Just gold. Great content, very interesting to see what happens at such high distances. I also loved your comparison x32 vs. M32 a lot ! Very in depth but never boring.
Thanks for sharing your knowledge with us Dave!
Thank you Tino!
I know right I mean "this guy" !!!- that says it all.
Honored!
@@DaveRat I'm also honored ! Dave, can I work for you ?
Always love great people. I do think we have info on our web site when we are hiring, though I don't deal with that side of things
definitely helps you visualize/appreciate what considerations those of us that design sports venues have when they jam the tv /radio folks up in the rafters of a 1.2 million square foot building.
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That was just insanely cool!
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So cool to just kick back and learn while you putter ❤️☮️🤙
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Really cool, Dave! Thanks again for another great video! 🙂
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Who else would do this? No one...ONLY DAVE and I love it!
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I was being cocky about Cat-snakes (worried about audio quality using let's say 10m stage Cat-snakes, not 3 miles😁).
Worries; XLR cabling (designed for audio fidelity for analog transfer), Ethernet cabling (designed for data integrity for digital transfer). Different cable specs for different applications. With Cat-snakes we are going to use cabling designed for transmission of digital signals for transmission of analogue signals. Without researching it, my technical brain said that it will negatively impact audio quality. You proved me wrong by showing it in practice! Brilliant! Thanks. I don't have to worry about using 10m Cat-snakes👍🏻🤟🏻😃
Good stuff and to be honest I knew it would work well but I did not realize that it would work that well better than mic cable and AES cable. I did other videos testing it as well as a 10 mi test
Very nice video ! just what exotic cable lovers need to see. a mic level signal doing 6 miles... jees !!! pretty good !!
Both surprised and expected. Surprised it worked with no special electronics to deal with long cables and expected as telephone cables are way longer.
@@DaveRat yep :) its just ideal to show people that are not from the field of pro audio :) that expensive cables 1000$ and up (for one meter of cable having a line signal.....) are completely useless.. we already knew... but yeah
Especially the power cords after 50 miles of ac lines on cables and 75 feet or 12Gauge solid conductor wire in the house walls, some kbuclehead buys a $5000 IEC cable thinking it will make a difference.
Makes me smile.
Cable rolls are collecting not only shunting capacitance C (depends on cable's quality and length - reducing upper frequencies), and serial resistance R (depends on cable's quality and length - reducing signal level), but serial inductance L too (depends on cable ROLLS summary serial inductance). This inductance is affecting passive dynamic mics (just voice coils, or voice coils + transformers like SM58); transformer output active electronics dynamic and condenser mics; playing games with shunting cable's capacitance. And the next input's impedance parameters are taking part in this game too, all it is rather complex...
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@@DaveRat Thank you very much, your videos are so simple and so educating!
Forgot to add - all the losses depend on the microphone's (or any other transducer's or gear's) output impedance. Lower impedance reduces affects depth. 8 ohms, or 50 ohms, or 600 ohms, or 10 kohms, etc., output impedances (passive or active) mean a serious difference in the signal loss in cables + other affects, including EMI/RFI noise and some phase shifting coming from LC components. But in the real life, we rarely have so long cables, so no reason for panic... :)
Questions I never knew I needed to ask!
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very cool dave, loved this video
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Interesting, I would have expected a significant drop in phantom power voltage. Thanks for testing!
Would have been interesting to measure how much of the 48V is still getting through ;)
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There will be a significant drop in voltage over even the 'shorter' 1.5 mile lengths, but it's dc and and most mics really don't need 48V except for some super high end stuff, like perhaps the Nuemann, but all that mean is its gonna lose some dynamic range and noise floor, hardly significant compared to the frequency rolloff's and cable induced noise at the lengths being talked about. Take away is... if you can put up with the sound degradation the phantom power can still fuel your condensers (unless you started with some crap deck that only sends out 12V and pretends that is good enough).
Even for a short cable the voltage can drop significantly from 48 Volts with a mic connected. That's because the phantom power standard is actually 48V fed onto pins 2 and 3 of the XLR through 6.8K resistors. So the resistance of the 6 miles of cable has a resistance far smaller than the resistors in the preamp feeding the power into the cable in the first place. It would be about 820 ohms added to the existing 6800, assuming 24 gauge copper mic cable. So the amount the voltage drops below 48V when the mic is connected would only be about 12% more with the 6 miles of cable than with a short cable. In reality this drops would be a bit more because I havent calculated the additional drop from the shield resistance, but its likely to be small compared to the twisted pairs. With one the Cat5e conductors serving as the GND wire rather than a proper shield, the drop would be more significant maybe closer to 35% more than without a long cable.
I did a video on phantom powering mics from multiple consoles and show the voltage drops
I loved this! Thanks for doing it Dave.
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Hey Dave! Awesome demo! I love this type of direct comparison. Two SMALL points: 1) The base-line Frequency response of your mixer seems a bit outta wack (i.e. larger deviations from 0 dB Transfer function than one would expect), and I think the changes in the response would be CLEARER (and easier to quantify) with a smaller vertical scale on the transfer function. It looks like you have ~+24dB to -15dB, or an ~ 39dB range. This range could be reduced to +/- 15 dB making the changes easier to see (A vertical scale of +10dB to -20dB or -25dB might be best to show the roll-off at the longer lengths) THANK YOU for making these videos.... informative and FUN!!!! - Sam.
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you is smart Dave. Love it man
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Always wanted to know the latency of such instances like this. Fantastic video bud
Hmm, well the electro magnetic waves travel about 60% the speed of light or 300,000 meters per sec.
So 9600 meters divided by 300,000 equals . 032 or approximately 3 ms wire latency.
That sounds like a fun test.
Dave, you always do the craziest things. I love it. :-)
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A new way for me to annoy my neighbors from even further away! Nice. :D
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Great/interesting demo. The HF roll-off of the pink noise generator over extremely long cable lengths (causing increased inductance, resistance, capacitance) might be attributable to generator's output impedance. However, if the output of the pink noise generator is coupled directly from its opamps, and does not have any series resistance or capacitance, the long cable length roll-off might be negligible. If its output is transformer-coupled, then that would also introduce losses. (All of this applies to microphone impedances as well.) Thank you for such a great demo!!!
I did the test with a mic and a pink so we can see or hear how each is impacted
Yes! And this is why your test is so cool, for it deals with "real world" values, typically 150 ohms. In theory, as the source (mic, pink noise, etc.) impedance goes down, the effects of cable losses (resistance, capacitance) would go down as well. Soooo, this test reveals that the resistance of the cables affects volume, while the capacitance of the cables affects high frequencies. If the source impedances were reduced from, say, 150 ohms down to an ideal zero ohms, these cable lengths would have no effect at all. Thanks again, Dave, for such a great test! Your efforts are much appreciated!
So cool and thank you Scott!
I do try and stay away from theory and assumptions and just plug in and see whenever possible
@@DaveRat Dave, like your other viewers, I really appreciate this valuable testing you're doing...AND THEN...generously sharing it with all of us on UA-cam. I'm very grateful. Sure, theory is nice, but to see this stuff in action is so cool. As a studio tech, I've always been fascinated with the reasons "why" things sound the way they do. For instance, what makes a 414 and a U47 sound different, or an SSL and a Neve sound different, or a Marshall and a Fender sound different, etc. It reminds me of music. Yeah, it's great to understand the theory behind different musicians' styles but, hey, nothing compares with actually hearing it, right? (BTW, you also get into the "why" of things when you ask and answer important questions like "Why crowded shows sound dull...", etc., and that's really cool too.)
One really important point you made during your testing is, despite any losses created with 6 miles of cable, you can then just reach up and tweak a tone control and get it all back again! Wow!
Thanks again for everything you're doing.
So cool and thank you Scott! Comments like this make the adventure worth doing
Wow, these tests of yours are always amazing! And thank you for sharing your experience, I learn from your video.
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wow....who wood dah thunk it!!!! thanx Rat!
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Dave Rat is our Mr. Wizard of sound. Love watching your experiments and that you just go for it and actually try it out.
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Super interesting video! I've hooked up a measurement mic with 100m of cable before and compared it to the direct response, with negligible error. Cool to see that even 10x that distance doesn't have a huge effect!
It might be worth noting that the error also depends on the input device's input impedance. Some ADCs have really low ii (
Is it the input impedance or the output 8mpedance of the mic that controls the overall line impedance?
My understanding is that lower mic output impedance allows longer cable runs with less hf roll off
@@DaveRat I consulted with the guys on my Audio Discord and worked out a long answer:
There are three main electrical properies of the cable, which cause signal degredation. These are the cable's resistance, capacitance and inductance. These three components form a passive circuit along with the two devices (mic and preamp), similar to a crossover circuit inside a passive speaker.
tl;dr:
High preamp input impedance reduces overall signal loss
Low mic output impedance reduces HF roll-off
Thicker cable=less overall loss, but more HF loss, relatively speaking
Long version:
Let's talk about resistance first, since that's easy:
First of all, we can say that at analog audio frequencies, cable resistance is the same for all frequencies (no need for silver plated audiophile snake oil).
The mic's impedance is small compared to the preamp's, so it has almost no effect here (similar to damping factor in amps).
The cable resistance causes a flat loss at all frequencies.
Looking at the lowest frequencies in your 6 mile test, we see a loss of about 7dB, which plugged into a calculator looks like the wire is 27AWG.
The Xenyx's input impedance is 2.6kΩ. The X32's input impedance for example is 5kΩ, so you'd see a 4dB reduction instead, compared to the 7dB on the Xenyx.
Time to talk about cable capacitance:
This is what causes the HF roll-off. It's basically a parallel capacitor, which is a 1st order LPF.
Preamp input impedance has close to no effect on this, it is indeed the source device's output impedance, like you said.
The Xenyx's is 240Ω, which I what we see in SMAART, I suppose?
You can generalize, that a device with half the output impedance will roughtly have half the HF loss.
SM58 is 150Ω, which would be better than the Xenyx already. KM184 is 50Ω, which would reduce that HF loss to only about a fifth, for example.
Now comes the wierd part, we don't really have to worry about, inductance:
This depends on cable layout. We know having a power cable on a drum/coiled up heats it up quickly because it's a)bunched up and can't transfer its heat to its surroundings well and b)a coil is an inductor, which forms a magnetic field.
Since you're sending a differential (symmetric) signal through twisted pairs of cable, the two magnetic fields cancel each other out and not much is happening.
If that signal was an unbalanced signal however, you'd have a series inductor in the loop, which forms a 2nd order LPF with the cable capacitance, making HF loss even worse. By how much I don't know, someone would have to test that.
Note that this is mostly an issue when the cable is still on the drums and you (probably?) won't have to worry about it when it's laid out in a straight line. Of course, sending an unbalanced signal through miles of cables will cause a lot of other issues, but that's what we have DI boxes for.
And for the cable properties:
A thicker cable will have a lower resistance, but higher capacitance. This means lower loss overall, but more HF-loss.
And also, we can just plug it in and listen
It's one of those things that you never wanted to know, you will never have any use to know, but you are still glad that you know it.
And ya never know if you will get a call to wire sound for a bike race in an area without wifi or cell service with battery powered speakers.
Phantom power is very similar the voltage present on a copper telephone line. The same thing happens to telco lines the farther you go out the more attenuation in the high end but in the telco world we employ what is called a passive load coil that helps to make up for the loss. Since you are using what is essentially telephone wire to run this test I'm not sure if the cables coiled up are effectively acting like a load coil and affecting your results positively or not. You could try to unroll them and repeat the test and place one roll up cable reel in the middle switching it in and out to verify weather or not it effects your high end.
Hmmm, comparing the impact of coiling of high bandwidth precision twisted pair Cat5e to telephone line may not be fully on point
Are you sure the twisted pairs of Cat5e would be impacted by coiling the same as telephone line?
Anyway, the test was to see how far audio and phantom would go down Cat5e and it well exceeded expectations.
So you think that if I uncoil it will go even farther than what is already too far for nearly all applications?
@@DaveRat You are correct they are not exactly the same telco twisted copper is is generally Cat3. I was just curious if there was any effect having them all coiled up.
www.fiber-optic-tutorial.com/wp-content/uploads/2014/12/leenetpic1.gif
My understanding is that perfectly twisted pairs should be immune to coiling inductance.
That said, nothing is perfect.
And I am not curious enough to uncoil 6 miles of cable and find out. At least not yet
@@DaveRat Yes I agree don't do that, make an intern or someone do it. LOL. just kidding. Love the channel by the way keep it up.
en.wikipedia.org/wiki/Loading_coil
Might want to talk with old radio engineers that used telephone dry lines that are cat3 for miles for broadcast feeds or studio to transmitter links. Yes, they had to have a device at the end to compensate for EQ.
Very cool. Yeah I was getting questions asking how far they can run analog down the Cat5e cable I designed.
Mainly looking at the 500 to 1000 meter lengths. But one customer wanted longer as well.
Well this was to show that down a mile or so without any additional stuff, it will work fairly well just plug and play
11:34 lmao "Let's go to 3 miles. Not the island"
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So if i decide to sing in the village nearby (Im a country singer you know) -I call Dave Rat and dont even have to leave my room . Cool indeed !
Wire it up!
Now add a launcher or cloudlifter and see what that does! Great content Dave!
Thank you Skeeter
Thanks for this. No idea why but i just had this weird assumption that too long of a cable would cause a crazy delay. You've obviously debunked that for me so thank you!
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Big like from London 👍
Thank you Dove!!
With regards to speed of signal transmission: the speed of Electromagnetic signals running through a copper cable is approx. 200,000 km / second. Very fast indeed! Meaning that you would need to have 200,000 km of cable in order to introduce a delay of one (1) second. That’s a lot of cable. A typical single pair mike cable weighs 65g/meter. 200,000 km of cable would weigh 13,000 tons (13,000,000 kg). As said above: that’s a lot of cable!
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It would be interesting to see the same test done with regular multicore just darting it back and forth down the line to see how it degrades.
Yes and compare to mic cable as well would be interesting too. Though I'm not sure I will go down that road.
Dave, it would be very interesting to see this test with a digital console sending a high amount of tracks down the different distances to see if there's any digital degradation once you start adding tracks. If I had that much cable I would try it myself...
Next try different consoles? See if different consoles can push 48v that far. Would also be interesting to measure heat on that pre circuit. Would also be interesting to see how much resistance was in that lenght of cable. As always ty Dave!
The phantom power spec is the same for all consoles.
My understanding is usually that couplers is where you usually lose your most power (especially with stranded, so check your 5e. Solid is more annoying to terminate, but would be better for insertion loss), so I'd be interested to see if you could push it further with just a longer cable instead of multiple connected spools.
I think that couplers do have an impact on data frequencies of 100k, 1 meg or higher, but this is analog over cat5. So the relative simple 20 to 20k is a lot more resilient and not impacted much.
Very interesting demo would it be possible for you to make a vid on how foh desks are switched in and out at festivals for all the guest engineers that would be a great help for me thank you I love your videos ❤️
Thank you Gerry. I did a video on the member side of my UA-cam covering how Rat does it.
love these experiments, now I also have a reference for people complaining that a 100m phantom run is too long haha
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That is one hell of a lot of inductor coils! I wish you would had measured the total resistance of 6 miles of wire. And also the inductance. Curious to know that.
Hmmm, it's 26 gauge wire so the resistance is an easy calc and twisted pairs cancel inductance
There is capacitance the phone company used to and inductors every so far to fix the response curve.
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Interesting! I use a program called ShareX to record screens to video, it will also record the laptop sound making it easy to align the clips in the editor. This allows me to avoid pointing a camera at the screen .
Yeah, I have a screen recorder on my personal laptops but that laptop is a shop measurement unit and we don't add software to it.
@@DaveRat very sensible! (Speaking as an IT professional ) , and you are up late, it being early morning here in Africa (-:
Good morning and great to meet ya!
Well we’ll well! Hahaha. This is even more Brilliant!!! Wonder what a cloudlifter or a line driver on one end “pushing” the audio rather than pulling the audio.
Just thinking if you would actually need this for simple monitoring this is great. Not for recording for any Grammy awards but hey. I bet someone would buy it. LOL.
this video is gonna go viral
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To be fair, the wires coiled like that make several inductors. If they were unwound, the results could have been different possibly.
Do coils create inductors when the wires are tightly twisted pairs?
Or does tightly twisting the wires cancel out the electro magnetic radiation needed for inductance to occur?
@@DaveRat You're absolutely right, these twisted pairs cancel the magnetic fields out so it doesn't matter whether the cable is rolled up or not.
What does happen, however, is that INSIDE the cable itself, the insulation between your conductors and the shielding create a small capacitence, and the cable itself acts as a small inductor. In RF engineeing we call this a transmission line. This acts as a low pass filter and therefore can limit the bandwidth of your signal. The higher the frequency or the longer the cable, the higher the losses, hence you lack your highs at the end of the line! This is also where the phaseshift comes from, regarding the distance is still really short taking the speed a signal travels through a wire in mind.
This is why RF cable in the GHz range is so incredibly expensive, the centre insulator has to be flexible yet have a very low dielectric constant.
Sounds right to me
There is some really early & interesting science on pumping _analog_ audio long distances. The focus was on extending telephone lines _before_ the invention of the triode vacuum tube. Three really inventive folks came up with versions of the "loading coil".
¶
If curious about this, please see Wikipedia for...:
#1 Oliver Heaviside
#2 George Campbell
#3 Michael Pupin
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AT&T bought Pupin's patent to stay out of legal battle, making him a very wealthy man. A physics professor at Columbia, the Department's building is named after him. A fascinating person, he was an inventor in several area and Edwin Armstrong was his student. _..._ /Mike
Great stuff and my goal was to see how the gear we have readily available to us responds to using it for long runs.
Taking all the theory and ideas based on gear we don't have and seeing how the gear we do have works!
Awesome vid!
Thank you Zumazmusic!
Very cool!
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A coaxial cable would theoretically be the perfect fit for this. That white stuff around the wire is there to make sure there's always a constant charge that stays the same whether it's one meter long or one kilometer
No it would not... The miracle of cat5/6 is the incredible well balanced (and different) twist density on each pair. If you tried to do this on unbalanced co-ax you would hear nothing but two cities worth of hum before the mic signal hit your preamps.
Coax does deal with high frequencies well as it has less capacitance but but the twisted pairs are better at rejecting noise.
But the test was to see how far phantom power would work and with coax, that would be easy, 0 feet.
@@DaveRat really!? So a coaxial cable can't carry phantom power at all?
Not without making it not phantom. Phantom is based on a 3 wire cable.
Though the series resistance will be 500 ohms, phantom current is quite low, maybe 20mA at the highest, so voltage drop should be 10v max. Many, but not all, 48v microphones would be ok with this.
Agreed
Cat5/6 has an inherent characteristic impedance of 110ohms - so it will handle 50 to 200 fairly well. You'll get some worse frequency rolloff on a 600ohm mic... and trying this with a guitar pickup... well, just lets not :)
Great video. 😃👍♥️
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I really like his shirt. It reminds me of a recent reddit post I saw...
Funny!!!
Hey dave , another classic vid , obviously u wud,nt run those cables spooled but but for instance if they were layed out how do they deal w/ heat dispersion, a mile though, absolutely amazing ,...
👍🤙👍, heat dissipation is only a concern with higher currents
Did you measure the voltage drop, I believe the phantom mics are specified 18-48V. Video idea, at what voltage will phantom mics not work. Nice video, thanks!
Not in this cable test. Some mics are 12 to 52, some say 48v. Many will work but they lose headroom at lower voltages. Thank you!
I am actually really impressed by the fact that anything even remotly related to the original signal would come out of a cablerun like that!
However i see a slight potential "issue" with the testing of the phantom power as i asume either the XLR splitter, the XLR switcher or maybe both have the grounds of all connectors bridged. What that would mean is that the sheild of the long cable would be in parallel to the sheild of the short cable run, almost eliminating the impact of it's electrical resistance.
In terms of signal strength there shouldn't be much of a difference with a balanced signal, however i do think that the impact on phantom power and maybe also sensitivity to EMI could be affected by this test setup.
Either way, this was a great video and an impressive test regardless.
Yes, on one hand the ground length is 25% of the miles but also the ground braid is much thicker than the twisted pairs and has a lower resistance.
So phantom travels at least 6 miles down twisted pairs of the 12 total it would travel, but the 6 miles of ground that it is not travelling is low resistance
So maybe the real world equiv of phantom down 4 miles or so
Now for a fun question. What practical or hypothetical applications does running analog audio over a mile even have?
I've been in large recording studio complexes with several studios where the audio from say, studio c's live room would get patched to studio a's control room, and the total signal path could be hundreds or even thousands of feet.
The idea for this video came from a customer buying Cat5e cable to put speakers up for a 1/2 marathon route 8n an area without cell service or WiFi
The question was "how far can I run analog over Cat5e? So I tested it and made a vid.
The 1/2 marathon had the drive unit in the middle. So 6 miles each way would do it and with shorter runs because there was a generator and the ability to refresh the signal at each speaker area evenly spaced on the route.
@@DaveRat Given that you can hire a StarLink ground station for about 300 bucks for 5 days, how did the cable solution compare?
The customer says it's still works great and it's been several years.
@@DaveRat Ah! Didn't realise it was a permanent gig....
My prediction before watching. 48V will work fine, the resistance of the cable won't be that significant in comparison to the 6.8K resistors the phantom is already being supplied via, though it will add some capacitance. The 48V should drop when it sees the uncharged capacitance, then come back up again as it charges, and work fine from then on out.
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A ton of cheap audio gear will put out more like 12-24v on phantom. It's amazing the number of preamps that tolerate it. I do have a few that want the full +48v however. Test first!
Dave you make very cool videos and I have learned a lot from you. I have a question concerning this video. Did you consider the fact that coiled cable reels may create millihenry choke coils which will inherently create a low pass filter in your experiment?
Sooo, that would mean that if indeed the twisted pairs did not counteract that occuring 2e could run even longer with less rolloff?
Awesome
Great video! I wonder how much of that roll off is due to the wires being coiled. They are acting like air core inductors. What would the difference be if the wire was straight vs coiled?
Twisted pairs are almost completely immune to coiling. Especially tightly twisted pairs like Cat5 cable has
Wonder what the voltage drop is. I know most condenser mics will run in 12v even when the spec is +48v, but I have a couple that are more sensitive to voltage.
Also be aware, that much wire will delay the signal a bit. Old osciliscopes used to use long coils of wire exaclty for that. Not enough to hear, but phase issues can arise.
Have you done this with a dynamic lol? Now i just need to wire my house in cat5 and add preamps to every room. :D
Hmmm, math calcs.
As far as delay, since sound travels about 200,000,000 meters per second in wire, the delay would be around .05 ms or about the equivalent of 1/2". In other words, the delay in the wire is less than moving the mic an inch further from lips
As far as the voltage drop, that is an easy calc as well,
Look up the resistance per 1000ft of 26ga wire, divide by 2, as there is 2 wires, then double it as it travels there and back. Then look up the current draw of the mic. Then apply ohms law.
I believe I did the calc in another comment here on the vid got don't recall the result, I think it was less than a 12 volt drop. But the cald will get ya close
The disapation of a 48volt phantom power microphone feed starts to deteriorate over the longer the distance! The expectations are typical from what we would expect on the principles of Ohm's Law! This is because for every 2 and a half centremetres within..say 12,800 metres (12 miles) before the signal enters three thirds below it's roll off threshold that it then becomes more apparent say around -128bB give or take!
It's only then that it starts to lose it's basic functionality such as it's power conductivity, impedance strength which is long before an acoustic delay becomes audibly noticeable! The longer the length of cable from it's source then the more of the odd popping noises and on many of occasions RFI (radio frequency interference) despite the cable being rf suppressed at the mixer or limiter/compressor point! Although upstandably the signal will be considerably weaker which will need to be amplified due to the increase in noise static! Another important factor that one may forget to take into consideration is the quality of the phantom power microphone cable for each drum reel regarding it's outer and inner sleeving and outer insulation! The transmission of live acoustic electrical signals during that of a live festival, concert is no stranger to acoustic hiccups whether it's cable cracks, phantom pops, rf interference, hum issues etc Using a Behringer feedback destroyer for ie resolves many PA problems but not all of them although the principles of cleaning up the signal are more or less the same aswell as the rate of acoustic feedback! So in summary it's really just an experiment to see how far up a professional graded XLR microphone cable takes before a delay becomes audibly noticeable! Technically, long after the signal becomes hardly audible from it's source!
I love the tech and theory and even more it's fun to test and see and hear what actually happens in the real world
@@DaveRat It really is absolutely fascinating Dave for you to actually put these live acoustic experiments to the test in order to ascertain whether there is some technical and mathematical truth to them thus debunking or confirming some of the sound industry's greatest myths! We can just imagine a very young Alexander Graham Bell conducting similar experiments with microphone's before the concept of the telephone arrived (back in 1876 I think) only for it to be improved much time later with a more efficient carbon telephone transmitter by the late Thomas Edison! 🙂👍
Thank you and let me know if you have myths I can test!
The small drop noted at the response could be from using many ethercon couplers
He llo Sono!!
Interesting. Yes etherc9m couplers do cause 8ssues for cat5s running data as the frequency is very high.
For analog over cat5e. Those ethercon couplers actually have much thicker wire than the Cat5e cable so they should have minimal impact. I believe the main causes of the drops are resistance from the long thin wire and capacitance from two wires that are very long being next to each other 8n the twisted pair
@@DaveRat Hey Dave, totally agree. But once someone told me that theres a little bit of oxygen between couplers that could cause a signal loss
Any connection will slightly degrade the signal, high speed data is especially impacted like 100k, 1 meg or above.
Analog audio is like 20k so it's a very low frequency and lower frequencies are less impacted.
There are 2 versions of neuteik barrel as well. One is way better for data than the other. For analog it makes no real difference which one.
I have no idea what any of this means except the fact that you can get a fairly clear signal that far without boosters or repeaters whatever they are called. Also, what is phantom power and what is it doing in this situation.
Phantom is a way to remotely send power to microphones that have small amplifiers in them, down shielded twisted pair cables.
Imagine running from FOH a mile to stage. How many companies would have enough cable protectors?
Not to mention hiring the Hubble🔭
@@dr.feelicks2051 "telescope not included"
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@@DaveRat 😂😂😂
Please test and compare it to 100 x 100m mic leads all connected sequentially. And also 10,000m of Monster cable. And 10,000m of unrolled cable. LOL!
What if it was unbalanced - does it pickup AM radio? Can you use an EQ to restore and flatten it out? The 48v Phantom should go for several km because that's what old analog PSTN phones ran from sent from the telephone exchange.
That sounds like a bunch of testing on more expensive ways to do what I already tested
What can be interresting, when you plug mic to 1input, and try to draw gignal from remaining chanel lines in Cat cable. How strong crosstalk analog induction in cat cables is, when working balanced/unbalanced.
Have you watched the vid I did on crosstalk in Cat5e with analog signals?
ua-cam.com/video/gGgPDEz5sNU/v-deo.html
@Dave Rat cool cool :) thanks
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I work at a high school and use Wall-Cats all over the place. The district is much better at installing Cat cable rather than multiple mic lines. My question is can you run DMX and audio over the same Cat line?
Yes, analog, dmz, AES3, and com can all run down the same wallcqt or catbox at the same time.
Just like with regular 4 channel audio snake.
Cool video, that high end was really dull by the end but what a testament to the distances one can achieve, so interesting the phantom power held out. :)
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That was 17 minutes well spent. Frequency response and level aside, I cant help but wonder about noise rejection and interference in a less friendly environment. That might be a more limiting factor.
Yes, those are concerns, yet the applications that long analog cable runs are most likely going to be used has a high probability of being in remote locations without wifi or cell signal and possibly dependant on power generators. So interference would be less likely.
very cool mate! just wondering do you know if line level has the similar response to roll off and length?
Well. The pink was not line level but it was a low impedance output. So what you see on smaart with pink is what line level will do and what you hear is what mics will do
Hi Dave. Two questions. 1: How on earth did you come up with this challenge? 2: You have now concluded that it is possible to run an analog microphone signal through several miles of cable with only a minor impact to the quality of the signal. But do you know why that is?
Well, before there was digital and fiber, analog was run everywhere. I believe analog was designed to run long distances.
Older designed mics like the RE20 have selectable impedances going down to 50 ohms That should allow it to run 2x to 3x farther with the same HF rolloff vs the 150 or 200 it is set to when sold.
Another way to look at this: if you ever run out of EQs but need a low pass filter pretty bad but have a couple km of cables...😂😂
Handy and practical too
I always wondered about this. I use a 100ft. 16 channel snake from my control room to my live room. I wondered if it made a difference going through that extra 100ft. Cable. The answer is no. At least I can't tell the difference. Not long enough.
This was not a test of maximum fidelity, just a test of function. I would say that 100 feet will make a slight difference that with low impedance sources would be inaudible but measurable. Shorter wires are better but the difference is very small
@@DaveRat
Wow, Yeah. I can't tell the difference. I'm sure on one of those computer frequency meters there would be a slight difference. I can't believe that you did sound for Soundgarden. Chris Cornell was one of my favorite musicians. It's a shame what happened to him. I was blown away. I've met a lot of big time musicians being in a touring band but never got to meet him unfortunately. Great Vocalist.
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I didn't see the whole video yet, but did you drive to the mic and see if it was working?
I can't give away the ending!
I wonder what would happen if that cable wasn't coiled in a small space, but in a straight line round trip, I think there would probably be a lot more interference
Hmmm, the customer that bought our Soundtools Supercat cable to run signal to speakers along a sporting event route said it still works great with no issues
A fellow senior grumpy engineer friend of mine who's too pretentious to bother commenting here himself because of fear of "noob relation" mentioned:
"Interesting test with the cable runs. I'm surprised that no one mentioned that the cables are in coils which will produce impedance even though the cables are shielded.
The common practice with extra lengths when running cables, is to lay it out in a figure 8 to avoid the problem."
Hmmm, I think there is some misunderstanding of shielded vs twisted pair. Twisted pair is inductance cancelling, Shielded is not.
Either way, if indeed the coils were to create issues, then we could go even longer, but I ran out of cables to use and the whole purpose of the test was to see how far phantom would power a mic.
Is your friend saying that uncoiling would achieve my goal of phantom not powering the mic?
@@DaveRat he made no mention of phantom power being lost over that distance. I think he was just grumpy to see the coils and overlooked the mention of it being twisted pairs. Cheers for your quick reply Dave! Long live coffee cat :3
Ha and awesome! Yeah, people like to spot things and spit out info as if they know what they are talking about.
Best thing to do is ask him for ducumentaion and a video of the testing he did to gain that knowledge.
@@DaveRat I think your education is more valid as you are far more relevant compared to an old grump who hasn't had a gig in two decades (nor embraced the digital era for that matter), I doubt running audio over twisted pairs is a concept he's even familiar with. If we're to do a similar installation but not use your specific branded cable, as long as we're using Cat 5e twisted, we should be fine for most installations (say for tie-lines in a studio where the runs would be no more than a few hundred meters?). I'm trying to help another peer of mine design and build a new studio space but classic analog cabling (mogami or the sort) gets pricey. I suggested some cat boxes and running the audio over twisted pair instead. Also does Sound Tools provide any solutions for the wall box that is more than 8 channels? Could we present a custom design and have that built out? say for 24 ch or more? Thanks for sharing your knowledge with us freely and publicly :-)
I'm surprised nobody realized that as soon as the signal was sent back up the cat5 again (looped through multiple pairs) the gnd return path (shield) was eliminated from the circuit since all the pairs share the shield down the cable and back! This cuts the overall length of cable the phantom power is using in 1/2, 1/3, or 1/4 (depending on how many pairs your looking in and out of), and cuts down in the amount of voltage loss at the condenser. It invalidates the question of how long can you run phantom power because only the +v is running the distance (and shared on 2 conductors, as is the nature of phantom power). To keep the test real you can't look back down multiple pairs, sorry!
Still an interesting test though.
Great observation! The ground does not carry any signal on balanced lines and all the signal travels down tristed pairs. So sound quality should not be impacted for better or worse
But yes, the doubling back does decrease the resistive losses to phantom power. Though with the supercat, the braid shield has so much copper, the resistive losses are minimal in comparison to the losses of the twisted pair wires so not doubling back should still be about the same.
With supercat sound, the pairs are individually sheilded and the doubling back would reduce some losses to phantom voltage
Very cool!
@@DaveRat I disagree, regarding the supercat sound cable and individual shields... All those shields come together to a common connector shell at both ends, so if your running the distance (and not looping back) then you will benefit from the less resistances of all 4 coppers sharing the load; but if you loop the signal back then, just like with the other cables in the test, you eliminate the shield length completely from the active DC circuit powering the microphone!
Also, with runs that long, even with "thick shield" I wouldn't discount the voltage loss from the shield over miles of cable.
The end result, though, as pointed out earlier, will likely be somewhere in the range of 10-15 volts of drop (depending of course on how much current the mic is pulling) which should have little to no effect on the most microphones if your source is 48v (I'm not doing the calculation myself just trusting the calculation I read earlier).
The super cat sound with individual wires would be lower resistance doubling back correct not disagreeing with that.
Say we had best case scenario and the shield resistance was eliminated completely that would reduce 1/2 of the total resistance the signal sees or a 6 DB difference.
But half of the cable has super thick grounds so the difference will be less maybe three or four DB differential between doubling back and not
@@DaveRat I think you misunderstood my point... There will be no loss of "signal" due to anything regarding the shield, because signal does not pass through the shield.
The point I was making is that regardless of which cable/shield type you are using, once you send the signal "back down" the pipe on another pair and pick it up at the end where you started, you have now effectively eliminated the shield (your best case scenario in real life!) from the active circuit powering the microphone! Even with the individuals shields, they all bond together at the Ethernet connector shell, and that is the only part of the cable that carries the - leg of current to the microphone! You won't lose db's off your signal but you will not be presenting the correct amount of voltage loss that a cable 2-4x the distance of the actual Ethernet cable jacket is.
Again, even with the shield as part of the circuit, it's probably not enough loss to shut down most mics if you have a solid 48v supply at the input end; but even with a "thick shield" it will add a measurable amount of resistance / voltage loss to the circuit, if it wasn't being bypassed by the loop back to the beginning in the cable. Either way, your no longer accurately measuring the correct voltage loss after that first 1.5 mile run, when you looped the signal back through different pairs.
your network cables act as a henry coil allowing for amplification when spooled even knowing cables are shielded .... you would have to unroll the cabling in order to get a better controlled test so you do not have the amplification from the spooled coils of wire, suggestion unrolling the coils into full lenth back and forth 100 meters at a time ... much less chance of amplification then the rolled coil even if cables are shielded.
best way to go long distances is xlr output from the board to a transceiver hub with xlr input/output and outputs to fiber cable, you can go up to 180 miles without any loss or a booster then the same on the other end, this fiber cable you can leave spooled because it does not carry a value for a henry coil when spooled no copper or any other combinations of metals incorporated into the cable ....this I can guarantee. if they would incorporate fiber cables into digital boards with remote stage boxes like the X32 you would not have to worry about electric issues at the main board and can use a separate power source all together even out of phase, it would not cause a problem, it would still be IO but by light instead of electric signals in the cable.
Hmmm, I am testing the worst case.
Also, tightly twisted pairs tend not to have much inductance.
If this was non twisted speaker cable, I would agree that there could be issues from coiling.
Anyway, I want the issues as I was trying to see how long the cable would be for the phantom mic to stop working
We get customers asking how long they can run analog down the Cat5e cables we manufacture, so Ihad some fun doing a test. And doing the test with the cable coiled means I can save from telling them, yeah. You need to spool all the wire into a big mess for it to work. Yuck.
For the touring and festival systems we supply, we can spit out fiber, Cat5e or analog to a multitude of locations.
And also it's important to remember that making things complex is not always better.
One application for long cable runs was for a 1/2 marathon announce mic and music with battery powered speakers along the route every 600 meters or so.
No wifi, no cell service area and fidelity is not a big deal.
Do ya use fiber and network and digital or just run some copper and be done? How long can the copper be? What will it sound like?
Those are the questions I was seeking to answer.
@@DaveRat I totally get ya, its definitely a cool video, I liked how you could see the roll off but not until over a mile in on the scope great visual perspective, I think cat5e is so much better then the old school snakes and can still be used as analog with your connectors thanks for getting back to me, I appreciate your videos. I am curious if you would be open to a vid with cat5e and a wireless transceiver set with encryption ?.. would you even consider a wireless transceiver set to send sound to stage ?
Hmmm, I don't really do vids on stuff that I am not pretty familiar with on some level.
As far as using wireless for transmitting to stage, as with everything, avoid complexity and avoid adding anything that can fail unless it brings district advantages.
Perhaps in a pinch but wireless frequencies are extremely scarce and we pretty much need power everywhere and running fiber with the power gets us signal everywhere
6 miles is wild distance of a cable run lol
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You forgot to show what that cat cable? Ethernet? looks like. Home studio and musician guys run XLR (including me)
Is it at the end of the video in the trailer?
@@DaveRat I found pictures at google :) "Catapult Cat 5 Analog Snake"
Cool and also maybe check out Soundtools.com catbox, cat tails,, wallcat, and cat rack for aluminum ones that won't rust or have the paint chip. Plus Soundtools has much nicer tails and versions no one else makes like the supercat tails
It acts almost like coils producing a low pass filter. And i say "almost" due to the 6db loss
Hmmm, are you sure that twisted wires form an inductor when coiled?
Maybe do some research on twisted pairs vs emf.
Good to know you can lol. Not sure why you would!
I could think of some situations where running super inexpensive sheilded Cat5e may be a more reliable, less expensive or less complex solution to other methods.
Bike race with announce speakers along the route in a remote location may want to weigh costs and complexities of setting up wireless transmission vs just running copper.
Also, in making soundtools analog over cat5e I am faclscinated to learn how much of the world still embraces analog over digital solutions for infrastructure.
Hospitals and building being wired with our Wall at boxes and super long cable runs and routing to multiple buildings.
As useful and fun as digital and wireless may be, running a copper wire is still a great solution for many applications
@@DaveRat When I was in the Navy I worked with deep submersibles, tethered UAV's. The most expensive part was the tether. It carried power and comms etc. Wired is always prefered. However not sure about miles of it hahahaha! And it, as you say, just works...
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That should debunk all shady claims by "sound experts" about cable length.
Yes and no. This shows function of signal level for utility purposes. Speaker level and higher fidelity applications, would need more testing.
Heh. He said ‘plug in the pink’. (Couldn’t help it!)
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Hello
Dave
I totally understand
however rather to do anything
I think it would be interesting to nevertheless have a credits in order to start from a base and it is up to me to consider your professional advice
Hmmm, ok