Hey Dave, I am no sound guy, but used to lug your gear around SoCal venues as a stage hand. It's really cool after years to finally get these lessons from you when I never had the opportunity to pick your brain on site. I really appreciate that you're taking the time to share your knowledge with the rest of us and the generations to come. That model makes so much more sense than all of the times lesser A1's have attempted to explain it to me.
Genius Prop! Great explanation of balanced lines. I have heard the term "common mode rejection " used to describe how noise that cuts across both lines is nulled.
It’s funny, after sound school ( 79’ ) there I was commercial audio, and a few years later BOOM! There it was, I understood phase relationship. I could cut a lacquer master, but couldn’t explain phase shift. I was able to articulate it, but I couldn’t tell you why. Total poser. You did an amazing job here. When ever I was bringing someone up , I would get to the lowest common denominator, and explain as if I were talking to a 6 year old. Thanks from a 66 yr old. Brilliant ☮️
Nice explanation Dave! Btw I own you my response to some SoundTools I received few months ago. Everything is just fantastic! We have 3 WallCat8s in parallel so we can easily handle some simple Theatre shows with 2 IN and 2 OUT from place one or two back to stage. We also get male and female CAT Tails, so if there is no digital sound through our Ethercon connection, we have another 4 IN or OUTS for small music venues with our 8 channel annalog console. It is simply fantastic solution and If I have enough money for long multicore Cat5 cable and everything, I will make my main annalog snake from CAT Rack! :) Cheers!
Awesome and thank you and super cool! Also we're coming out with a cat rack 16 really soon that will have four ethercon in and outs 16 XLRs and two DB25s in a single rack space
🤙👍🤙 cool and also I had soundtools create discount codes for UA-cam channel members, I believe it is 10% off. I will post the code in the member community chat in case you don't have it.
Love the shirt Man You could've mentioned CMRR Figure in preamp specification is how well the common mode rejection is working The secret behind balance line transmission is the differential amplifier longtailed pair USB cables are also balance
CMRR is starting to get into the electronic engineering of amplifier design. Dave does often straddle the electronics engineering and the sound engineering. When watching this video I was always thinking of CMRR but that's probably because I cut my teeth on the electronics. Balanced is used in RF as well. Ethernet on twisted pair is balanced. Pretty much the go-to method of removing noise.
Yes noise rejection is critical with cat cables and a significant focus of the design. And yes mixers that have balance signals all the way through do exist though with digital being so common now it's not as relevant.
Something you don't always realise or really touch on much untill you start getting into circuit board design (althhough it's actually quite obivous in hindsight) is that "ground" in a single ended line isn't just sitting there doing nothing. A circuit needs to be a loop, so the ground wire is where the "return" currents travel through. Ideally we useually want our grounds to be referenced to 0 volts, but they never actually are 0 volts if there is current running through them, as if they have small return currents flowing through them and there is a resistence (which copper has) there MUST be at least a small voltage acording to Ohms law, it's just they are idealy very low impeedence paths connected to a very low potential points to encourage the signal to use that as a return path, instead of coupling into other random things. However, if you say have a circuitboard, have a signal trace running down the middle, and one around the outter edge, and a "ground" current return trace for the middle trace that goes around the outside of the board it will most likely couple into the other signal trace on the outside of the board, EVEN though it's a ground trace at very close to ground potential (becuse there is still current flowing through it). Now this really becomes a huge issue when you get into RF teritory, and with audio it's no so much of an issue, but audio is still susceptable to RF interfearence and crosstalk, so it's always worth keeping it in mind that "ground" (which I hate calling it for return paths) is not 0 volts IF it's part of a return path for a signal (other than at the AC 0 point crossover, periodically, and temporarily), even though it MAY be connected to an actual consistently 0 volts chunk of metal or the actual ground it's self. A single piece of metal can simaltaniously have voltege and no voltage in different places if certain criteria is met, but if there is signal return there MUST be at least a small voltage between the points the current is traveling to and from. A ground plane is a good example of this, as for a 2 layer board (as an example) the return currents in the ground plane will follow the signal trace above it through the ground plane (due to emf coupling), not spreading too far into the rest of the copper around it, which remains at much closer to 0 volts than the path it's self. As a result it's always imporatant to route audio signal and audio ground together in wires, because you minimse the loop area, as it's an antenna essentually, and both wires can pick up that RF, just we are taking the signal half way, so some of that noise if introduced after will not make it to the output, but there are scenarios where this isn't the case and paying attention to your return path is very important (ground feedback loops being a prime example of this) ;).
So cool thank you. And but you say kind of relates to balance lines in that one of the advantages of balanced lines is they don't use the ground for return path. And the ground can be dedicated purely to protection from noise and a shield. Though current traveling through a ground shield does induce noise into the lines especially on non-balanced lines, with microphones though since there's no ground loop and no voltage or current on the ground except for the RF, it tends to be pretty immune
@@DaveRat Indeed! It's part of the very reason differential pairs started to be utilised in this manor for sensative external signal cabling to begin with, because of their far superior cmr (common mode rejection)! 😉👍
What do you think about balanced (microphone, 2 wires and shield) cables, does ground (shield) connection need to be soldered? I've read different opinions about this in manuals, some recommend to solder it from only receiving end, some from sending end. Also how "pseudobalanced" soldering works from unbalanced outs to balanced ins. Thank you very much for your videos.
The ground wire or shield is not necessary for balanced audio but is important for shielding especially with a microphone because it's the only way that microphone cable gets a ground. As far as lifting the ground on one end of a cable to prevent ground loops this can work but not with microphones. Only connecting the shield on one end usually doesn't help and it's always better to solve the ground loop rather than try and get around it that way
@@productionneuftrois9488 A good thing to have laying about is a temporary "gound loop locator cable" which does have it's sheild disconnected, and swap out cables one by one, if it doesn't change the hum, it's probably not part of the loop (unless you have multuple, then it becomes more complicated to solve and you may need more than one botch cable) BUT if when changing to your special cable the hum goes away, you know current is flowing in the ground sheild wire you just disconnected and you have just found part of the loop, and then you can follow the signal path unit to unit with your special cable kind of mapping out the current path. The last units on either end of where you chased down the loop to being are your prime suspects, and their grounding would need to be looked at and possibly revised if not just fixed. (there are other ways to deal with them too, as this only really works for more simple set ups, and can be a real pain in very complex systems with hundreds of grounded units etc.) You can also start unplugging wires one at a time to initially find the loop, but if that is the unit that is the source of the signal causing the loop, but not part of the actual ground loop it's self, it could give a faulse positive, so it's better to do it with a temporary cable with it's ground lifted so the signal path is left in tact and only the ground connect is lifted.
i spend all day explaining why the TRS cable my customer is using is causing noise. "but i got an 1/8" TRS to 1/4" TRS cable and I input into my mixer. it totally fits and my mixer has TRS inputs. i read it in the manual. the cable you sold me is defective!" me shaking my head and taking a big breath, getting ready to explain all the TRS applications, to someone who has supposedly "been doing this for 30 years...
Related question: Why is the XLR Pin 1 (ground) Not Connected thru to the other end of a 4-XLR CAT box -;to Ethetcon - to 4-XLR CAT box?? Thereby defeating Phantom Power??
Ground pin1 is connected on all SoundTools analog over cat products. If you are not seeing ground connection the most likely issue is one or more cables in the signal chain does not have a properly connects shield to metal housing RJ45 or metal housing RJ45 inside the ethercon shell. Test the cables. All SoundTools analog over cat products will allow one or more channels to be independently Phantom powered. Here's a video where I show Phantom power, ClearCom and AES 3 simultaneously running down a single cat 5 cable into sound tools cat boxes ua-cam.com/video/0J3FWq--fCM/v-deo.htmlsi=9dljd16lGKb525xv
What can’t this man do. Tell me is there an advantage to using this method to a line voltage pa or general multi sound setup IE to a venue. The only reason I query is to minimize interference from many other feeds of electrical and data while all contained in conduit just wondering if 2 core plus earth is a better investment to figure 8 even though output and speakers are all just standard +\- binding posts not XLR etc. PS nice call on the L’acousticrig for Jam’s tour.
My understanding of quad cables is that by having four wires two for the in polarity and two for the out of polarity, it's purely a refinement. All the principles are the same except quad cables are a bit better at making sure that noise signals induced on the wires are more identical and therefore can be better canceled out.
i wish you went a step farther with "psuedo-balanced" or impedance-balanced circuits. e.g a TRS 1/4" output of a small budget mixer, where there is only positive and ground, but still has the noise rejection/cancellation of a true balanced line using an additional resistor to match the impedance of the circuit
This is a common misconception. Symmetry, which is sharing the opposite voltage across two lines, does not make a cable balanced. All it does is increase the maximum signal the cable can carry. If you do the math you can see that the noise rejection done by balancing the cable works if you transmit the signal entirely down one cable or the other, or split them evenly. Balancing means that you have a shared voltage reference that is separate from the safety/electrical ground, which helps prevent ground loop interference. I highly recommend watching the Audio Engineering Society sessions by Bill Whitlock on grounding.
I understand that we can use asymmetrical balanced lines as long as neither line is grounded. Since there is no ground reference for balanced lines generated by microphones and transformed , the offset to ground is irrelevant That said, symmetrical balanced line naturally occur and for all practical purposes the existence of asymmetrical balanced lines is irrelevant in practice. But as you said, unbalanced lines that are ground references will fail to fully utilize all available input gain as the offset can cause one line to overload before the other in the input circuit
@ yes, it's a sadly too common issue that equipment manufacturers don't properly implement balanced IO and will tie neutral to ground, totally eliminating the benefits of balancing, believing symmetry is all that matters. Properly implemented balancing is almost entirely impervious to interference, as I believe you've shown in some of your past videos.
Maximum signal the cable can carry.... Dude! We are talking mV and mA at most, the CABLE isnt going to boil or arc! So, thats not exactly what you meant. What you really mean is that IF the signals have a common reference, none of it gets eaten by common mode rejection. You also miss that if there isnt a common reference, your noise rejection is worse (due to the effective signal being weaker)
Sorry, but this is just plain wrong and a very common mistake. Balanced does not mean complimentary voltages, it might be, but it does not have to be. Interference rejection still happens when the signals are both zero. The correct definition of balanced is matched impedances of both sides, the output and input impedances form a Wheatstone bridge. Check videos and papers by Bill Whitlock for the correct explanation.
Hmmm, balanced line or are you referring to more specifically what Bill discusses which is that the lines do not need to be evenly and equally balanced in order to achieve noise reduction? I do enjoy the nuances and accuracy so I will raise you up another level. I am describing how balanced lines work. The fact that the lines do not need to have equally balanced voltages in relation to ground in order to achieve noise cancellation is interesting and relevant but does not change how balanced lines work. Nor does that subset of function make the description of how balanced lines work incorrect.
@@DaveRat You are not describing how balanced lines work because you are only talking about a voltage model special case without considering impedances. Complimentary voltages do not help noise cancellation at all, they only might reduce their interference into other nearby lines, like in a multicore or dense patchbay wiring. They are a hangover from centre tapped output transformers, which do have equal output impedances. People look at such stages and incorrectly assume that the complimentary voltages are the important part. This mistake has been propagating for decades, but repeating it doesn't make it right. Do you think an output is balanced if it has complimentary voltages and different impedances each side? How does your model explain that?
I think one of the more common examples in usages of balanced lines in audio relates to dynamic microphones. Where it's the perfect trifecta of extremely low level susceptible to noise, commonly needing long distance runs often in noisy environments and is naturally balanced with equal impedances to ground of the two signal carrying wires. This is where a lot of problem solving and troubleshooting and exposure to the assets and issues of balanced lines occurs for the majority of audio humans. Understanding why we use three pin XLRs instead of quarter inch cables on microphones I think is probably the most helpful aspect and focus of this video. That's it things like bridge mono amplifiers or modern amps that actually have both terminals being equal opposite voltages is another example but due to the higher level of the signal there's no real concern with noise induction so so line balancing is an artifact rather than a focus. If someone's designing condenser microphones or output preamps, then we start to run into a need to try and keep the impedances to ground identical but also again, kind of like the amplifier scenario we're not really dealing with ultra low level signals that are extremely susceptible to noise where line balancing is so critical. So overall in the most practical sense, The things we need to be line balanced the most tend to be dynamic microphones and transformer DI boxes, which naturally and inherently present equal and opposite voltages with near identical impedances to ground. So the focus of the video is on people understanding the most important part of what they're most likely to experience and not get into the weeds on stuff that is more friends and highly improbable to be experienced by people seeking understanding of balanced lines. At least in the early stages before they go on to start designing professional audio gear What I do find fascinating is that guitar and bass pickups have never really evolved into the balanced line realm yet they are perfect candidates and are naturally balanced in their outputs. Converting a guitar to a TRS 1/4" would you wonders for helping with noise reduction. Making lower impedance guitar and bass pickups would be excellent for longer cable runs without the sound of the cable impacting the sound of the guitar. But it's also kind of cool to embrace the flaws as part of the sound and art
Not against that adventure but also I'm not sure how useful that concept is to most people unless designing and building equipment. I find it interesting but I'm not sure that there's many other people except for a select few including yourself that will do as well. Seems that alll the people that want to know about impedance balancing already know about impedance balancing More fun to do videos helping people understand things they don't know.
As much as I LOVE your stuff, the problem with the piece of your child's toy, that you were about to throw out from your attic, but thought would be useful in an explainer video ;) is that it misses a crucial aspect of ground wires. They wrap AROUND the microphone pos/neg wires. They are not in the middle. By wrapping around the exterior they are the first conductive material that external electrons meet and therefore are drained away before hitting the mic electrons. I believe that's right? I think "balanced" is a somewhat unfortunate name. "Shielded" which is sometimes used too, is better in some regards! Again, LOVE your stuff. Which I had more time to watch.
Balanced lines don't need a shield or a ground. And whether the ground wraps as a shield or is a separate wire down the middle makes no difference to balancing. Also, electrons travel no faster in the shield than they do in the regular wires. So the signals and electrons all arrive at the same time anyway
@@DaveRat If I may quibble. A balanced line without a shield or ground is what really? A voltage must have a return path. There is no such thing, right, of a single path (wire) of microphone voltages. Another way of putting it is all microphones MUST have two wires. So why call it balanced, or anything else? It is two wires where current flows from magnetic movement. What really distinguishes a "balanced" line is the return path is separated from the ground, or external electrons, right? As for the speed of electrons, I don't think I said anything about that, only that is drains external electrons away from the microphone circuit, which is always a circuit, always two line? Does that make any sense? So in your explanation, you did it in reverse, you talked about what if you put the ground with the pos/neg. Shouldn't you have explained it the other way. How to remove the "ground" from the pos/neg circuit? You create a 3rd line. It always comes after.
The balance line is its own return path there's two wires and they form the electrical circuit. A a dynamic microphone is a coil of wire a Merced a magnetic field and when that wire coil moves it generates electricity on the two ends of the wire. No ground is needed. A shield is beneficial in reducing the amount of noise but not needed for the electrical function of the circuit. On the receiving end it can be just a transformer again without a ground on the input of the transformer or coming from the mic. Or it can be an electronic circuit they inverts the polarity of one of the Lines and sums it with the other one. It is not till you get to the output of this circuit or the debalanced part of the circuitry that a ground reference becomes pertinent. The output of the transformer well also be balanced naturally but in order to transport the signal it's quite common too ground one of the legs of the output of the transformer and have the other leg be the signal at which point the signal is no longer balanced and a ground or common is involved. While the signal is balanced any noise signal induced on both lines equally will be canceled out when the signal is debalanced. After the signal has been debalanced any noise induced will get embedded in the signal and will become much more difficult to eliminate.
@@DaveRat Thanks for response. I hope you can continue to bear with me. Sorry, I have to disagree with your first statement. Yes, theoretically, a balanced line has its own return path and forms an electrical circuit. But only theoretically. I think that's important. Because it's like, um, fantasy ;) No electrical circuit exists in a vacuum, so to speak. A microphone voltage is useless by itself until it is amplified and right there it connects to another electrical circuit. And then static electricity between the wires and air, what circuit is that? So I mean, sure, a balanced line forms an electrical circuit but in the real world is that the end of it for you? ;) 2nd sentence. When the coil moves it pushes electrons in one direction or another. They bump into each other, right? The magnet doesn't create "electricity" (electrons). Each end of the wire either has a pressure or vacuum, so to speak. In the 3rd sentence, again, SORRY!!! but you're talking about this stuff in reverse. EVERYTHING is grounded in a sense. All atoms are charged, the difference is how reactive they are to magnetic fields, right? Copper is VERY reactive. Wood, not so much. One man's noise is another man's music. Noise is only what we call electron pressures we don't want in our world. Shielding IS needed for every electrical circuit to work in the real world, right? Or let me put it this way, you see your job as getting a good signal from all the musicians on the stage and out to the audience. You think signal first. But couldn't one look at your job as getting ALL EXTRANEOUS signals out of the system? Chicken or egg? What do you really mean when you write, "While the signal is balanced any noise signal induced on both lines equally will be canceled out when the signal is debalanced" Can you explain that to me in terms of a single electron? What is "noise" but a fancy term for a voltage we want shunted to another circuit?!!! IMHO opinion, talking about a "balanced" line as being possible to exist without a second circuit (ground) doesn't make any sense. Not trying to criticize. Just trying to explain how I think your explanation could be different. It's what I love about you. You talk about the real world. But I feel here you're talking too much like an engineer with electronics theory and not about what follows what in the real world. Man plugs in microphone. God laughs ;)
Hmmm sounds fuzzy in the understanding Step back and look at what actually works and is easy to demonstrate Cut pin 1 in a mic cable and the output is identical. More susceptible to noise but the output is unchanged. No ground needed. Cut pin 1 on a mic pre, same results As far as noise signals induced on balanced lines and the ability to cancel out the noise, Google common mode rejection or CMMR
Please disable automatic audio translations when uploading a video. The AI voice makes me want to vomit, dislike and close the video. I don't want to have to switch my whole youtube to english in order to hear the original audio tracks to 90% of the videos.
This is all sorts of wrong (which is par for UA-cam). The defining characteristic of a BALANCED audio interface is that the IMPEDANCE of both signal legs are IDENTICAL with respect to ground (it's essentially a WHEATSTONE bridge). Please read the various papers by Bill Whitlock (AES Fellow and head of Jensen Transformers) for further enlightenment.
I'm not sure if that's correct. Whether there's a ground or not is irrelevant to a balanced line. All that a balance line requires really is that the signal is produced across two lines. Introducing differences like impedance differences on one or the other line and not impacting both equally may or may not impact the balancing. In reality the signals on the balance line need to be opposite but they don't need to even be equal with reference to ground, for line balancing and common mode rejection to work.
Differential vs. common mode signals. Also, common mode rejection of the preamp is dependent on its differential input resistors matching where 1% matching will result in 40dB CMRR (common mode rejection ratio) which isn't all that great compared to a a circuit with CMRR trim which can chieve in excess of 100dB CMRR.
Hey Dave, I am no sound guy, but used to lug your gear around SoCal venues as a stage hand. It's really cool after years to finally get these lessons from you when I never had the opportunity to pick your brain on site. I really appreciate that you're taking the time to share your knowledge with the rest of us and the generations to come.
That model makes so much more sense than all of the times lesser A1's have attempted to explain it to me.
So cool and thank you Derek!
Genius Prop! Great explanation of balanced lines. I have heard the term "common mode rejection " used to describe how noise that cuts across both lines is nulled.
great visual as always thank you for thinking outside the box to help understand the inside.
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It’s funny, after sound school ( 79’ ) there I was commercial audio, and a few years later BOOM! There it was, I understood phase relationship.
I could cut a lacquer master, but couldn’t explain phase shift. I was able to articulate it, but I couldn’t tell you why.
Total poser.
You did an amazing job here.
When ever I was bringing someone up , I would get to the lowest common denominator, and explain as if I were talking to a 6 year old.
Thanks from a 66 yr old.
Brilliant ☮️
So cool and thank you!!!
Thanks a million Dave. This illustration makes it very easy to grasp
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Hey, again a complex theme very clear explained! Thanks, Dave!
Thank you Edwin!
Nice work, this concept of a differential signal is very common in many disciplines I've discovered over the years.
Agreed and thank you
I have been surprised that they use it in measuring brainwaves for electroencephalography as well. But it makes sense.
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Each of your videos always blew my mind away! Thank you for the awesome content
Super cool and thank you!!!
Nice to watch your explanations every time.
Wonderful and thank you
Great demo! First time's a charm for you, it seems.
Very cool and thank you Chris
Love these videos, I'd rather watch this then a dynamic EQ tutorial anyway.
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Nice explanation Dave! Btw I own you my response to some SoundTools I received few months ago. Everything is just fantastic! We have 3 WallCat8s in parallel so we can easily handle some simple Theatre shows with 2 IN and 2 OUT from place one or two back to stage. We also get male and female CAT Tails, so if there is no digital sound through our Ethercon connection, we have another 4 IN or OUTS for small music venues with our 8 channel annalog console. It is simply fantastic solution and If I have enough money for long multicore Cat5 cable and everything, I will make my main annalog snake from CAT Rack! :) Cheers!
Awesome and thank you and super cool! Also we're coming out with a cat rack 16 really soon that will have four ethercon in and outs 16 XLRs and two DB25s in a single rack space
@@DaveRat That sounds cool, fantastic!
🤙👍🤙 cool and also I had soundtools create discount codes for UA-cam channel members, I believe it is 10% off. I will post the code in the member community chat in case you don't have it.
Well done! Thanks for the explanation.
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brilliant demonstration!
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Thanks for explaining!
Awesome and thank you
Nice video Dave. Calculations And measurement are importent. But to visualise it is hard and importent tot explane IT all.
You die it. Thanks
Yeah there's plenty of people doing the testing and showing the data. Michael is to help people actually understand the concepts
Thats a really cool way of demonstrating this. Thanks!
Thank you and very cool
Now I see HOW it works. Thank you for this!
Awesome and thank you
Cool. Something I actually didn't know from my EE degree. Thanks.
Super cool and thank you
Loved the first PA of yours in FOH nice award good video as always.
Wonderful and thank you!
Great Video 😃👍♥️
Achievement unlocked, Dave the Puppet Master! Interesting video as usual ;)
So cool thank you! 👍🤙👍🤙
I’m here for exactly this video!!!!
Awesome!!
Love it Dave!
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Good explanation.
Very cool and thank you
@@DaveRat i wish to do better with my audio - esp for UA-cam steaming - so thanks for sharing your knowledge
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This was awesome. You are awesome.
thank you!!
Love the shirt Man
You could've mentioned CMRR Figure in preamp specification is how well the common mode rejection is working
The secret behind balance line transmission is the differential amplifier longtailed pair
USB cables are also balance
CMRR is starting to get into the electronic engineering of amplifier design. Dave does often straddle the electronics engineering and the sound engineering. When watching this video I was always thinking of CMRR but that's probably because I cut my teeth on the electronics. Balanced is used in RF as well. Ethernet on twisted pair is balanced. Pretty much the go-to method of removing noise.
@ Yeah And there are mixes which remain balance all the way through the mixer
Yes noise rejection is critical with cat cables and a significant focus of the design.
And yes mixers that have balance signals all the way through do exist though with digital being so common now it's not as relevant.
Something you don't always realise or really touch on much untill you start getting into circuit board design (althhough it's actually quite obivous in hindsight) is that "ground" in a single ended line isn't just sitting there doing nothing. A circuit needs to be a loop, so the ground wire is where the "return" currents travel through. Ideally we useually want our grounds to be referenced to 0 volts, but they never actually are 0 volts if there is current running through them, as if they have small return currents flowing through them and there is a resistence (which copper has) there MUST be at least a small voltage acording to Ohms law, it's just they are idealy very low impeedence paths connected to a very low potential points to encourage the signal to use that as a return path, instead of coupling into other random things.
However, if you say have a circuitboard, have a signal trace running down the middle, and one around the outter edge, and a "ground" current return trace for the middle trace that goes around the outside of the board it will most likely couple into the other signal trace on the outside of the board, EVEN though it's a ground trace at very close to ground potential (becuse there is still current flowing through it). Now this really becomes a huge issue when you get into RF teritory, and with audio it's no so much of an issue, but audio is still susceptable to RF interfearence and crosstalk, so it's always worth keeping it in mind that "ground" (which I hate calling it for return paths) is not 0 volts IF it's part of a return path for a signal (other than at the AC 0 point crossover, periodically, and temporarily), even though it MAY be connected to an actual consistently 0 volts chunk of metal or the actual ground it's self.
A single piece of metal can simaltaniously have voltege and no voltage in different places if certain criteria is met, but if there is signal return there MUST be at least a small voltage between the points the current is traveling to and from. A ground plane is a good example of this, as for a 2 layer board (as an example) the return currents in the ground plane will follow the signal trace above it through the ground plane (due to emf coupling), not spreading too far into the rest of the copper around it, which remains at much closer to 0 volts than the path it's self. As a result it's always imporatant to route audio signal and audio ground together in wires, because you minimse the loop area, as it's an antenna essentually, and both wires can pick up that RF, just we are taking the signal half way, so some of that noise if introduced after will not make it to the output, but there are scenarios where this isn't the case and paying attention to your return path is very important (ground feedback loops being a prime example of this) ;).
So cool thank you. And but you say kind of relates to balance lines in that one of the advantages of balanced lines is they don't use the ground for return path. And the ground can be dedicated purely to protection from noise and a shield. Though current traveling through a ground shield does induce noise into the lines especially on non-balanced lines, with microphones though since there's no ground loop and no voltage or current on the ground except for the RF, it tends to be pretty immune
@@DaveRat Indeed! It's part of the very reason differential pairs started to be utilised in this manor for sensative external signal cabling to begin with, because of their far superior cmr (common mode rejection)! 😉👍
Ageeed
이론에 대해서 잘 배우고 갑니다. 감사합니다.
Very cool and thank you!
Awesome shirt!
Mambo
@@DaveRat But of course. Also talented musicians - check out "Dog Trumpet" - not just a shirt, also the brothers' band.
What do you think about balanced (microphone, 2 wires and shield) cables, does ground (shield) connection need to be soldered? I've read different opinions about this in manuals, some recommend to solder it from only receiving end, some from sending end. Also how "pseudobalanced" soldering works from unbalanced outs to balanced ins. Thank you very much for your videos.
The ground wire or shield is not necessary for balanced audio but is important for shielding especially with a microphone because it's the only way that microphone cable gets a ground.
As far as lifting the ground on one end of a cable to prevent ground loops this can work but not with microphones.
Only connecting the shield on one end usually doesn't help and it's always better to solve the ground loop rather than try and get around it that way
@@DaveRat Thank you again! It would be nice to see some videos from you about ground loop solving experiences.
That's a good idea and an important skill will see what I can do
@@productionneuftrois9488 A good thing to have laying about is a temporary "gound loop locator cable" which does have it's sheild disconnected, and swap out cables one by one, if it doesn't change the hum, it's probably not part of the loop (unless you have multuple, then it becomes more complicated to solve and you may need more than one botch cable) BUT if when changing to your special cable the hum goes away, you know current is flowing in the ground sheild wire you just disconnected and you have just found part of the loop, and then you can follow the signal path unit to unit with your special cable kind of mapping out the current path. The last units on either end of where you chased down the loop to being are your prime suspects, and their grounding would need to be looked at and possibly revised if not just fixed. (there are other ways to deal with them too, as this only really works for more simple set ups, and can be a real pain in very complex systems with hundreds of grounded units etc.)
You can also start unplugging wires one at a time to initially find the loop, but if that is the unit that is the source of the signal causing the loop, but not part of the actual ground loop it's self, it could give a faulse positive, so it's better to do it with a temporary cable with it's ground lifted so the signal path is left in tact and only the ground connect is lifted.
Cool concept. Are you sending a signal over a true XLR cable in your example here?
Any 3 conductor connector will work and XLR is the most common at least for audio. Though balanced down 1/4" TRS is common.
Love it!
I learned something! Shocker! Must still be a couple neurons banging around in there.
Awesome!!
Pretty good a little rough yet but it made it on my sound playlist.
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Cool thank you 😃👍
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i spend all day explaining why the TRS cable my customer is using is causing noise.
"but i got an 1/8" TRS to 1/4" TRS cable and I input into my mixer. it totally fits and my mixer has TRS inputs. i read it in the manual. the cable you sold me is defective!"
me shaking my head and taking a big breath, getting ready to explain all the TRS applications, to someone who has supposedly "been doing this for 30 years...
awesome video
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Related question: Why is the XLR Pin 1 (ground) Not Connected thru to the other end of a 4-XLR CAT box -;to Ethetcon - to 4-XLR CAT box?? Thereby defeating Phantom Power??
Ground pin1 is connected on all SoundTools analog over cat products.
If you are not seeing ground connection the most likely issue is one or more cables in the signal chain does not have a properly connects shield to metal housing RJ45 or metal housing RJ45 inside the ethercon shell.
Test the cables.
All SoundTools analog over cat products will allow one or more channels to be independently Phantom powered.
Here's a video where I show Phantom power, ClearCom and AES 3 simultaneously running down a single cat 5 cable into sound tools cat boxes
ua-cam.com/video/0J3FWq--fCM/v-deo.htmlsi=9dljd16lGKb525xv
Suggestion: make the colors of your lines the same as the scope signal traces to remove one mapping-change in your great presentation.
Great idea
I've heard that using balanced wires between devices that don't even support balanced input or output can help reduce noise.
Yes, using balanced cables on unbalanced input and output circuitry can still have some benefits and offer some common mode rejection.
What can’t this man do. Tell me is there an advantage to using this method to a line voltage pa or general multi sound setup IE to a venue. The only reason I query is to minimize interference from many other feeds of electrical and data while all contained in conduit just wondering if 2 core plus earth is a better investment to figure 8 even though output and speakers are all just standard +\- binding posts not XLR etc. PS nice call on the L’acousticrig for Jam’s tour.
Kewl kewl!!!!
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👍 Noice...,
The devil in me wants to see the model for a star-quad cable.
My understanding of quad cables is that by having four wires two for the in polarity and two for the out of polarity, it's purely a refinement. All the principles are the same except quad cables are a bit better at making sure that noise signals induced on the wires are more identical and therefore can be better canceled out.
nice, save me from russia dave 😅 finally something to watch
Greetings to Russia and thank you!
The demo could be better using same colors on scope and model. (from a fan!)
Yes it's a great idea I wish I had thought of!
cool
Thank you
i wish you went a step farther with "psuedo-balanced" or impedance-balanced circuits. e.g a TRS 1/4" output of a small budget mixer, where there is only positive and ground, but still has the noise rejection/cancellation of a true balanced line using an additional resistor to match the impedance of the circuit
Will ponder that. This vid was all about simple basics. I hope you get back into more complex soon
This is a common misconception. Symmetry, which is sharing the opposite voltage across two lines, does not make a cable balanced. All it does is increase the maximum signal the cable can carry. If you do the math you can see that the noise rejection done by balancing the cable works if you transmit the signal entirely down one cable or the other, or split them evenly. Balancing means that you have a shared voltage reference that is separate from the safety/electrical ground, which helps prevent ground loop interference. I highly recommend watching the Audio Engineering Society sessions by Bill Whitlock on grounding.
I understand that we can use asymmetrical balanced lines as long as neither line is grounded.
Since there is no ground reference for balanced lines generated by microphones and transformed , the offset to ground is irrelevant
That said, symmetrical balanced line naturally occur and for all practical purposes the existence of asymmetrical balanced lines is irrelevant in practice.
But as you said, unbalanced lines that are ground references will fail to fully utilize all available input gain as the offset can cause one line to overload before the other in the input circuit
@ yes, it's a sadly too common issue that equipment manufacturers don't properly implement balanced IO and will tie neutral to ground, totally eliminating the benefits of balancing, believing symmetry is all that matters. Properly implemented balancing is almost entirely impervious to interference, as I believe you've shown in some of your past videos.
Very and yes
@@DaveRatwould be nice to have a vid reg. that fail implementations too.
Maximum signal the cable can carry....
Dude! We are talking mV and mA at most, the CABLE isnt going to boil or arc!
So, thats not exactly what you meant.
What you really mean is that IF the signals have a common reference, none of it gets eaten by common mode rejection.
You also miss that if there isnt a common reference, your noise rejection is worse (due to the effective signal being weaker)
Sorry, but this is just plain wrong and a very common mistake. Balanced does not mean complimentary voltages, it might be, but it does not have to be. Interference rejection still happens when the signals are both zero. The correct definition of balanced is matched impedances of both sides, the output and input impedances form a Wheatstone bridge. Check videos and papers by Bill Whitlock for the correct explanation.
Hmmm, balanced line or are you referring to more specifically what Bill discusses which is that the lines do not need to be evenly and equally balanced in order to achieve noise reduction?
I do enjoy the nuances and accuracy so I will raise you up another level.
I am describing how balanced lines work.
The fact that the lines do not need to have equally balanced voltages in relation to ground in order to achieve noise cancellation is interesting and relevant but does not change how balanced lines work.
Nor does that subset of function make the description of how balanced lines work incorrect.
@@DaveRat You are not describing how balanced lines work because you are only talking about a voltage model special case without considering impedances. Complimentary voltages do not help noise cancellation at all, they only might reduce their interference into other nearby lines, like in a multicore or dense patchbay wiring. They are a hangover from centre tapped output transformers, which do have equal output impedances. People look at such stages and incorrectly assume that the complimentary voltages are the important part. This mistake has been propagating for decades, but repeating it doesn't make it right.
Do you think an output is balanced if it has complimentary voltages and different impedances each side? How does your model explain that?
I think one of the more common examples in usages of balanced lines in audio relates to dynamic microphones.
Where it's the perfect trifecta of extremely low level susceptible to noise, commonly needing long distance runs often in noisy environments and is naturally balanced with equal impedances to ground of the two signal carrying wires.
This is where a lot of problem solving and troubleshooting and exposure to the assets and issues of balanced lines occurs for the majority of audio humans.
Understanding why we use three pin XLRs instead of quarter inch cables on microphones I think is probably the most helpful aspect and focus of this video.
That's it things like bridge mono amplifiers or modern amps that actually have both terminals being equal opposite voltages is another example but due to the higher level of the signal there's no real concern with noise induction so so line balancing is an artifact rather than a focus.
If someone's designing condenser microphones or output preamps, then we start to run into a need to try and keep the impedances to ground identical but also again, kind of like the amplifier scenario we're not really dealing with ultra low level signals that are extremely susceptible to noise where line balancing is so critical.
So overall in the most practical sense, The things we need to be line balanced the most tend to be dynamic microphones and transformer DI boxes, which naturally and inherently present equal and opposite voltages with near identical impedances to ground.
So the focus of the video is on people understanding the most important part of what they're most likely to experience and not get into the weeds on stuff that is more friends and highly improbable to be experienced by people seeking understanding of balanced lines. At least in the early stages before they go on to start designing professional audio gear
What I do find fascinating is that guitar and bass pickups have never really evolved into the balanced line realm yet they are perfect candidates and are naturally balanced in their outputs. Converting a guitar to a TRS 1/4" would you wonders for helping with noise reduction. Making lower impedance guitar and bass pickups would be excellent for longer cable runs without the sound of the cable impacting the sound of the guitar.
But it's also kind of cool to embrace the flaws as part of the sound and art
Dave... Now explain impedance balanced.
Not against that adventure but also I'm not sure how useful that concept is to most people unless designing and building equipment. I find it interesting but I'm not sure that there's many other people except for a select few including yourself that will do as well.
Seems that alll the people that want to know about impedance balancing already know about impedance balancing
More fun to do videos helping people understand things they don't know.
@@DaveRat Yeahhhhh said really slowly, you are correct! Thank you for the awesome videos!!!
Very cool and thank you Heve, I appreciate the input and comments and interactions. 🤙👍🤙
Balanced = Common Mode Rejection
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As much as I LOVE your stuff, the problem with the piece of your child's toy, that you were about to throw out from your attic, but thought would be useful in an explainer video ;) is that it misses a crucial aspect of ground wires. They wrap AROUND the microphone pos/neg wires. They are not in the middle. By wrapping around the exterior they are the first conductive material that external electrons meet and therefore are drained away before hitting the mic electrons. I believe that's right?
I think "balanced" is a somewhat unfortunate name. "Shielded" which is sometimes used too, is better in some regards! Again, LOVE your stuff. Which I had more time to watch.
Balanced lines don't need a shield or a ground. And whether the ground wraps as a shield or is a separate wire down the middle makes no difference to balancing.
Also, electrons travel no faster in the shield than they do in the regular wires. So the signals and electrons all arrive at the same time anyway
@@DaveRat If I may quibble. A balanced line without a shield or ground is what really? A voltage must have a return path. There is no such thing, right, of a single path (wire) of microphone voltages. Another way of putting it is all microphones MUST have two wires. So why call it balanced, or anything else? It is two wires where current flows from magnetic movement. What really distinguishes a "balanced" line is the return path is separated from the ground, or external electrons, right? As for the speed of electrons, I don't think I said anything about that, only that is drains external electrons away from the microphone circuit, which is always a circuit, always two line? Does that make any sense?
So in your explanation, you did it in reverse, you talked about what if you put the ground with the pos/neg. Shouldn't you have explained it the other way. How to remove the "ground" from the pos/neg circuit? You create a 3rd line. It always comes after.
The balance line is its own return path there's two wires and they form the electrical circuit.
A a dynamic microphone is a coil of wire a Merced a magnetic field and when that wire coil moves it generates electricity on the two ends of the wire.
No ground is needed. A shield is beneficial in reducing the amount of noise but not needed for the electrical function of the circuit.
On the receiving end it can be just a transformer again without a ground on the input of the transformer or coming from the mic.
Or it can be an electronic circuit they inverts the polarity of one of the
Lines and sums it with the other one.
It is not till you get to the output of this circuit or the debalanced part of the circuitry that a ground reference becomes pertinent.
The output of the transformer well also be balanced naturally but in order to transport the signal it's quite common too ground one of the legs of the output of the transformer and have the other leg be the signal at which point the signal is no longer balanced and a ground or common is involved.
While the signal is balanced any noise signal induced on both lines equally will be canceled out when the signal is debalanced.
After the signal has been debalanced any noise induced will get embedded in the signal and will become much more difficult to eliminate.
@@DaveRat Thanks for response. I hope you can continue to bear with me. Sorry, I have to disagree with your first statement. Yes, theoretically, a balanced line has its own return path and forms an electrical circuit. But only theoretically. I think that's important. Because it's like, um, fantasy ;) No electrical circuit exists in a vacuum, so to speak. A microphone voltage is useless by itself until it is amplified and right there it connects to another electrical circuit. And then static electricity between the wires and air, what circuit is that? So I mean, sure, a balanced line forms an electrical circuit but in the real world is that the end of it for you? ;)
2nd sentence. When the coil moves it pushes electrons in one direction or another. They bump into each other, right? The magnet doesn't create "electricity" (electrons). Each end of the wire either has a pressure or vacuum, so to speak.
In the 3rd sentence, again, SORRY!!! but you're talking about this stuff in reverse. EVERYTHING is grounded in a sense. All atoms are charged, the difference is how reactive they are to magnetic fields, right? Copper is VERY reactive. Wood, not so much.
One man's noise is another man's music. Noise is only what we call electron pressures we don't want in our world. Shielding IS needed for every electrical circuit to work in the real world, right?
Or let me put it this way, you see your job as getting a good signal from all the musicians on the stage and out to the audience. You think signal first. But couldn't one look at your job as getting ALL EXTRANEOUS signals out of the system? Chicken or egg?
What do you really mean when you write, "While the signal is balanced any noise signal induced on both lines equally will be canceled out when the signal is debalanced" Can you explain that to me in terms of a single electron?
What is "noise" but a fancy term for a voltage we want shunted to another circuit?!!! IMHO opinion, talking about a "balanced" line as being possible to exist without a second circuit (ground) doesn't make any sense. Not trying to criticize. Just trying to explain how I think your explanation could be different. It's what I love about you. You talk about the real world. But I feel here you're talking too much like an engineer with electronics theory and not about what follows what in the real world.
Man plugs in microphone. God laughs ;)
Hmmm sounds fuzzy in the understanding
Step back and look at what actually works and is easy to demonstrate
Cut pin 1 in a mic cable and the output is identical. More susceptible to noise but the output is unchanged. No ground needed.
Cut pin 1 on a mic pre, same results
As far as noise signals induced on balanced lines and the ability to cancel out the noise, Google common mode rejection or CMMR
Please disable automatic audio translations when uploading a video. The AI voice makes me want to vomit, dislike and close the video. I don't want to have to switch my whole youtube to english in order to hear the original audio tracks to 90% of the videos.
Interesting and thank you. Will do
This is all sorts of wrong (which is par for UA-cam). The defining characteristic of a BALANCED audio interface is that the IMPEDANCE of both signal legs are IDENTICAL with respect to ground (it's essentially a WHEATSTONE bridge). Please read the various papers by Bill Whitlock (AES Fellow and head of Jensen Transformers) for further enlightenment.
I'm not sure if that's correct.
Whether there's a ground or not is irrelevant to a balanced line.
All that a balance line requires really is that the signal is produced across two lines.
Introducing differences like impedance differences on one or the other line and not impacting both equally may or may not impact the balancing.
In reality the signals on the balance line need to be opposite but they don't need to even be equal with reference to ground, for line balancing and common mode rejection to work.
Differential vs. common mode signals. Also, common mode rejection of the preamp is dependent on its differential input resistors matching where 1% matching will result in 40dB CMRR (common mode rejection ratio) which isn't all that great compared to a a circuit with CMRR trim which can chieve in excess of 100dB CMRR.
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