Its truely amazing how much bs narratives and sneaky marketing affect the audio industry (all markets I suppose). I find it remarkable how people just parrot Social Media myths like its scientific fact. It just takes one Influencer to mention something relatively believable, and it becomes the new standard. People seem to forget that most of these people are financially motivated to keep you watching and/or buying. Thank you for keeping it real, and sharing what you learned 👊.
Than you for a good video! Something I understood after many years was that the speaker sees the damping factor as a series resistance of the output impedance of the power stage and the resistance of the speaker cable. Say the output impedance is 0.02 ohms gives 8/0.02=400. If we have a short or thick cable, it doesn't matter. resistance in copper 0.0175 ohm mm2/m. i.e. if you have 1 m of 2.5 mm2 i.e. 14 gauge it gives 0.007 ×2 ohms. 8/0.034=235. But if you have 5 m of 0.75mm2 i.e. 19 gauge (which is more common with midrange and treble as they don't have to cope with so much power) gives 0.116x2ohm. This gives 8/0.252=31. Then it doesn't matter with 400 or 2000 in damping factor because the cable accounts for all the resistance. Would be interesting to test different cable lengths.
Great testing. I think you need to compare the input and output signal. You can do this by subtracting the one signal from the other in audacity. If there is a difference in draping factor, you would see different peaks of the difference.
Maybe disappointingly similar results, but helpful testing nonetheless. Another interesting research topic related to output impedance of amplifiers and their ability to control the speaker cone would be voltage drive vs. current drive. I've read some anecdotal evidence and couple research papers from those who have experimented with current-driven speakers, would be cool see more of unbiased testing and objective data to see if there's some truth to the alleged benefits of current-drive amplifiers
I've owned some really nice class AB amps over the years from ARC audio, Precision Power, Zapco c2k/ Reference..Some of these amps are now highly regarded and have some of that old school SQ mythos from the 90's/ early 2000's. I've used these amps with anywhere between 300-500 watts of rated output on some very nice subwoofers . Bottom line is these amps all had damping factors above 400 and up to 600 and costed sometimes $600-$1500 USD some 20 plus years ago( do the inflation calculations if you like). Today I'm using a $150 sub amp again on some really nice subwoofers and I can absolutely tell no difference.
Long comment but relevant: These talking points or selling points about amp specifications from manufacturers all these years can be applied to multiple facets of sales in the industry from pushing or marketing these huge ofc power/ground cables for amplifier use, to "high end" RCA cables, to Sound deadener ( I could literally write an article about that market) among other things is just about larger sales/profit margins when they are mostly (not 100% cases but most for sure) total dimishing returns for the consumer/hobbyist. For just listening to music, sub amps that are capable of 2000 rms can still be connected with a 4 awg ofc power/ground and will be supplied with adequate voltage and current. Full range amps most certainly can be powered with 8 awg ofc almost always (yes OFC is better than CCA at least they get that right). These overkill situations with 2/0 awg plus are needed really for the guys that do the DB drags and I think for some cases that's overkill too. For the most part the companies try to sell you wire that is $5.00-$10/ft instead of $1/foot because it helps their profit margins (nothing more). The same can be said all these years about sound deadening material and let me tell you having been in this hobby for 25 years I have spent my fair $hare of money on that $tuff which only added more weight to my car, made my bank account shrink, and made my door panels or roof have a solid sound when tapping on it instead of a ringing sound ( wow how useful). The past two systems I have installed I have not used hardly any of that stuff except for maybe here or there to act as a decoupler for surfaces that needed some isolation to keep from pressing together. These last two setups have had the least amount of rattles out of all my others. What makes the most difference for eliminating rattles in a car stereo designed for quality sound playback is not sound deadener treatmnent but knowing a few things about midbass/subwoofer integration. Most guys cross their sub LPF's way too high (@80-120 HZ) and the same for their midbasses. That's mostly where these rattles and buzzes are coming from. Too much energy in the (80-150 HZ) areas. Subs aren't supposed to be midbasses. The best thing a fellow can do to clean up rattles and buzzes is to use a solid baffle ( wood or high density plastic) for the midbass with a weather stripping type material behind it when screwed to the metal inner door and keeping their crossover points for their sub/ midbass around 50-70 HZ LPF/HPF 24DB. Depending on how loud you listen while it might not totally eliminate buzzes and rattlles it most certainly will reduce them far more than any amount of overpriced sound deader material you add to the car. Try it out and you also might find that it helps to eliminate sub localization.
This is very interesting I have always wondered about the Schitt Aegir2 with a Damping Factor of “>10” which is the lowest I have ever seen I don’t have one but the reviews are very positive and based on your testing that makes sense 🙏🙏🙏
Still doing the mythbusting work nobody else is doing online. I remember in the 90's damping factor was a selling feature. In theory it matters, but in real world, apparently it doesn't. Even when I bought my current JL sub amps I saw the damping factor was 500 at 2 ohms and thought well, that's good. :)
in general, I agree with you. If you look from an acoustics point of view, there is no difference. but your graphs show differences in the factor. I think that if you connect a resistor instead of a speaker, the bottom graph will look more like the sound you are sending. I think that the peak after the end of the sound, and the graph of its fall, is the factor that we are looking for. this part of the graph is the electricity that returns from the speaker and the faster it becomes zero, the higher the damping factor
Interesting results, maybe we need more power or excursion to get an effect? It would also be interesting to have the same amp driven on different loads, and how that affects everything concerning damping factor. Therefore you might need a chassis in 4 and 2 Ohm, harder to do I know :)
The results from the mic measurement vs the electrical output from the amp should (at least in theory) lag about 90º from each other. The mic basically measures acceleration from the air in front of the cone, so the peaks of the mic values should align with the crossing points of the electrical input. With other words, the peak from the mic reading should be aligned with the changing directions (or polarity) of the electrical sine wave. When there's maximum voltage from the amp on the top and bottom of the sine wave, there's no acceleration from the cone, so the mic reads "zero". There's an awesome video of subwoofers by Alpha Sound about this subject.
I don't quite understand why all amps have such huge overshot at the end of any burst. Kind of wierd. The Stereophile magazine made similar experiment with very similar test signals to check speaker cables influence on speaker damping. And, as I recall, they captured overshoots at speaker terminals that were up to 2-3% of burst test signals in amplitude. But at the amp terminals those overshoots were next to zero. ("What a Difference a Wire Makes" by Ben Duncan | Jun 12, 2020 | First Published: Dec 1, 1995)
the overshoot comes from the dc blocking caps in the signal path of the amp. the charge up during the positive half wave and then even tho the signal goes to 0 and stays there they still have to discharge causing that overshoot. in other terms they introduce a phaseshift so the signal doesnt start on the same part of the wave and doesnt end on the same part so you dont completely end on 0
@@sedon7098 Isn't that overshoot a very high distortion then? Like 10-20% of the test signal? While typically modern amps have a distortion way less than 0.1%.
@@dwindeyerThis channel is devoted to testing of mobile audio equipment (“car audio”). Considering the outrageous amount of intentional distortion inherent in most music played in such systems, I think such artifacts would be buried in the very high road and engine noise when vehicles are actually in motion. A note re the Visiton - it looks to be one of their “full-range” models very commonly used by home audio DIY builders, and would very often be high passed and reinforced with either passive or actively power woofers/subs at higher frequencies than used in this test. Not that this is intended to disparage the test, or dispute the results - indeed, i thought it performed rather well in comparison to purpose built drivers with substantially more powerful motors. Nicely done, sir.
Would you mind sharing your raw audacity info. I am quite curious about cone control comparisons. And wha the effect of back emf might have on the results.
@@paul7000 It has to do with reliability and cleanliness. JL amp will last you ages, probably longer than the car. If you are planning in upgrading, that might not be of any benefit to you. But if you want an amp that will never cause you any problems,a JL or any other big brand will.be solid.
@@RAW-CAt you must be right, raw-cat, but it all seems like marketing bullish*t until I see test results. That's why I am turning my attention to your unbelievably useful videos like this one, where we can measure what is worth paying for. Without test like you do it all looks like a promise or voodoo marketing. How can we know that what they say is true without testing? I appreciate your videos and I am waiting for next videos to come.
So as far as I understand, every speakers has output a half cicle more than the one contained in the input signal, right? So the woofer are producing big distortion of the signal they have to reproduce. I did not expect that! How would perform a smalles driver live the ones currently used by many hi fi tower speakers manufacturers? Let say a 6,5 “ or 5,5”? Have you ever tested such drivers? Thank you and congratulations for your video!
@@RAW-CAt I see, maybe build an enclosure for the smaller driver and run it to max unclipped output of the weakest amp, then compare with other amps at same voltage? Thank you so much for your effort and exploration, I just feel like there must be a way to measure this more accurately.
@RAW-CAt- Ive been doing some research on how damping factor maters more as the freq. gets lower.Also how the resistance of the awg., & length of the speaker wire is usually why we can't hear the difference of a damping factor of 100 or @ the most 200. Example: the resistance of a 10ft, or roughly 3meter, 12 awg speaker cable can only pass a damping factor of 200. So smaller gauge, or longer cables would restrict more. I would like to see a 4 gauge cable, approximately 3ft, or 1meter long, wired to a 4 ohm woofer, @ 10 Hz, to see how much a damping factor of 100, 200, 400, & even 1,000 might change the detail, & impact of that freq.!? I have in my Large SUV, 4-Fi built D2 18s(with 33mm of X Max, & 3,500 r.m.s. 4 inch coils), in about a 850 Liters/30 cu. Ft. ported enclosure, tuned way low! Powered by a 17k amp. My wiring options would be .25= not going to try for this test, 1 ohm, 4 ohms, or 16 ohms. My amp is rated with a damping factor of 400 @ 4 ohms, so @ .25 of an ohm👀yikes= a damping factor of only 25, 1 ohm= 100, 4 ohms= 400, & 16 ohms= 1,600! This would be a great test, but i am unable to because i am disabled, & have not been outside in almost 5 years!
@@RAW-CAt the output signal when playing the same sections of sine waves. It'd be interesting to see if they still have that overshoot with a non-inductive load
One thing about it💁 ive never had a great amp without high damping.. ive never had a good amp with low damping .. and ive never had a bad amp high damping.. and i dont think anyone else has either... So it seems to me damping even at minimum shows use of quality parts and design go hand and hand and generally result a good df rather deemed useful or not..
Recording the amp output with a speaker connected means you're recording the amp + Back EMF of the driver, not just the amp itself. Or am I missing something?
Hi friend! I hope you can give me your opinion. I was using an audison bitone.1 and then it went to valhalla. Now i need a new DSP. My options here are Helix mini dsp and alpine pxe-0850x for similar price. Any other option is way over my budget. I run a morel hybrid ovation 6 2way kit and a jl 10w6v2, so i dont really need more than 6 channels. The car is a ford fusion with sync 3. Which one would you choose between the Alpine and Helix? Thanks man!!! Very nice channel!!!
If 6 channels is enough, go with the Helix. It will be smaller and easier to install. However for having a future proof system with possibility to upgrade, I would choose the Alpine with more channels.
Nerijus I have a comment/question about the last statement you made in this video. You suggest when picking an amplifier to generally choose one that’s the cleanest AND has the most power. I get that but what has me confused is that in just about all of the distortion graphs you’ve posted of different amplifiers you’ve tested, the least amount of THD present is generally just below rated power of the amplifier. Right before it jumps way up into clipping. I may be reading the graphs wrong but the general trend in most of them is a downward trend in THD as the power output goes up to a certain level and then a sharp rise as the amp reaches full output power. In that case would it make more sense to choose an amplifier with lower power output for driving midrange and tweeters? Especially if you listen at moderate levels somewhere around 90db? I know there’s drivers out there that can play that level, and some slightly above, with just 1watt of power. So even accounting for good headroom would an amplifier that outputs around 30-40 watts at its lowest THD be a better choice than a more powerful amp that has its lowest THD at around 90-100 watts? I’m talking about just for midrange and tweeters. And I’m just using those wattages as an example. I have no clue what real world wattages would be to drive midranges and tweeters to a modest listening level while still maintaining adequate headroom for dynamic peaks. Thanks for all your hard work putting out these videos.
Yes, you are absolutely correct. An amplifier with less rated power might be cleaner than a more powerful one at lower wattage. However, that is mainly THD+N. For a lot of amplifiers THD is a straight line and shoots up only before clipping. Noise is the thing that raises the curve at lower power levels. However, if the noise is very low and is not audible, it does not matter much. The problem is that these days there are not many low power amplifiers. You can fing old school 4x30W, but not today..
@@RAW-CAt Thanks for clearing that up for me. I actually have an old school MTX 4320 Thunder series amp that I bought new back in 1994 I think. It’s rated at 4x40 but the birthsheet actually shows a lot more. It’s a very clean amp and was a direct competitor to the old Alpines that you use. Mark Eldridge actually won several world competitions using these amps in his early 4 Runner builds. I have been using it since then up until recently when it started to pick up some alternator whine.. I switched it out to a JL HD600 and it’s way too much power for what I’m using it for and just doesn’t sound as clean as the old MTX. If I didn’t live in the US I would ship it to you for testing. I’m pretty confident it would measure every bit as good as your Alpines.
I strongly encourage you to bandpass filter that output. You think you have only 40Hz, but you don’t. Those sharp edges of the waveform at the start and end of it have energy at other frequencies- high frequencies. Think of it this way. Anything that changes in time faster than your smooth sine wave - any turns in that wave faster than what you see in your sine wave- means there are higher frequency components in there. Going from flat to suddenly starting into the sine wave has that. Ditto on the end of it. Stopping on a dime needs a fast rate of change - aka a high frequency.
I'm not sure why my previous comment got deleted. Perhaps b/c I included links in it. But, the quick version was that you can take your single cycle from REW, save it as a WAV and in Audacity, select that bit and copy/paste it to the middle of your 1.3s or so clip (or just pad the beginning with silence.). Then, analyze, plot spectrum. You'll see a massive amount of high frequency energy in there. If you run the Generator, CEA-2010 in REW to make it, you'll see far less. Next, though, just run both a high-pass and a low-pass filter on your sample -- say high-pass at 20Hz and low-pass at 80 Hz with a steep cut. The same plot spectrum will show the effect as you're now far closer to just having energy at 40 Hz. Finally, try something in REW like square wave, 1Hz, duty cycle 1%, and a 3s duration to make a WAV that has clicks at 1Hz. Super low right? Plot the spectrum of that (just select one if you like) and you'll see an almost linear decay that goes all the way out to the highest frequencies. Making that sharp transient of a square wave actually has energy at all sample-able frequencies.
I wonder if the damping factor myth will ever go away? BTW, I have repeated this elsewhere, but make a loudspeaker draw the same current from LF to 100KHz (current EQ) and the speaker will always behave like it sees a zero Ohm output impedance from the amplifier. *_Any_* amplifier! You can now even use a fairly high output impedance tube amplifier and it will still look like zero Ohm. No, I am not kidding because I am listening to this right now.
You should have also tested the cables and termination as they have resistive values and can negate any damping factor of an amp. So if you habe an amp with a DF of 500 and another with 25, but use terrible cables ans high mass termination, you can bring both damoing factors to almost the same. For instance, the amp of a DF of 500 lets assume that is at 8 ohms. 8÷500=0.016 output impedance. The amp of a DF of 25 has an output impedance of 0.32. Now lets use 2 different resistive values for speaker cables. Lets use .250 ohms and .00350 ohms. The amps with a DF of 500. .016+.250 = .266 which to find out the DF of thst outout impedance lets keep it at 8 ohms. 8÷.266 = 30 DF. Now lets try that with the .00350 cable. .016+.00350=.0195 which is a df of 410. Now lets try the amp of a DF of 25 .32+.250 = .57 which is. DF of 14. And for the other cable. .32 + .00350=.3235 which is a DF of 24.72. You see how much cables and termination can negate the DF of a higher DF amp. With the high resistance cables, both amps would sound the same with the bass. This is also why a lot of people think all amps sound the same. Their cables can be negating the differences in DF.
All measurements were done with very short oversized cables, so resistance is minimal. Off camera I compared those measurements with an 8 meter long cable that has higher resistance, however there were 0 difference between the measurements..
All true. And all irrelevant. The DC resistance of the voice coil is in series with all the other resistances. The DC resistance of the voice coil is typically about 60-70% of the rated impedance of a cone speaker. Lets say 5 ohms for an 8 ohm speaker. A few milliohms of cable resitance or connection resistance is a rounding error. The amount of electrical damping the loadspeaker experiences is totally dominated by its own resistance, unless the amplifiers output impedance is measures in ohms, not milliohms.
@@RAW-CAtcables that I saw in the video were relatively thin. Plus, crocodile clips can have high contact resistance. Unless this wasn't the test setup actually used?
Well 40hz free air is pretty hard to hear, wouldnt ih be different when an driver is mountet in an enclosure and measure in the port (if portet enclosure) or better measure the pressure in the cabinet.
Of course it would be different. However the purpose of the test is to see how the amplifier "controls" the driver. Not a system with acoustic air suspension or port resonances, only the driver itself.
@RAW-CAt thats also My point. You are measuring the driver in free air with a mic thats designet to measure sound. Most subs don't play 40hz or it barely to hear free air. If you put it in an enclosure in a car, you got cabin gain and also the output from the driver in the cabinet. Here it should be a lot easier for Even the mic to measure or Else if you measure the pressure or with the mic in the port, it should be a lot easier to pick up for an mic.
I think you need a low-pass after the Focusrite Interface. The burst you are generating contains high frequeny, this is why the speakers behave so different from the electrical Signal. I think it's quite rediculous to evaluate a result more than relative.
@@PlatypusPerspective hi, at the beginning and the end if you want. Zero line to sine transition ist like a transition, different to a contiuous sine. This is why I think a low pass would Help. Do you agree that what the Amp outputs is very different to your sine? It is the sidebands being added by turning the sine ON and off. Does that make any sense? Visually the high frequencies are in the sharp corner between the Zero line and the ascending sine. IT is almost like a rectangle.
@@thomasschwarzenberger8943 Hi there, we'd need to see the waveform at the input of the amp to be sure how closely it is able to follow it. We're taking it on trust that REW is creating an ideal waveform, and that the DAC is outputting it faithfully. It seems likely it is, at least at the start of the sine wave which looks extremely good to me, I can't see any hint of a discontinuity there, it seems pretty much exactly as it would be if it was the zero crossing to the second half-cycle if there had been a negative swing preceding it. Have you noticed that the subsequent divergence of the wave is due to developing a DC offset? The discontinuity at the end is the waveform terminating at the correct time but pushed off the zero value by the offset amount. Again, we'd need to compare the different stages of signal processing to see where this originates. It relates to reactive energy storage in the signal path, and several people have requested comparative tests into a purely resistive load to see how much of the variance is due to the speaker's reactance. If we could observe either that a resistive load resulted in the theoretically correct waveform at the amp output, or that the amp input signal is in fact the exact theoretical REW waveform, implying the same thing, we could form a better conclusion.
@@PlatypusPerspective I saw that, and was thinking this looks Like a coupling capacitor being discharged. Speaker ground, Signal ground and supply ground are the same? Could it be that the Amp causes just a ground shift?
@@thomasschwarzenberger8943 Yes, my initial thought was the overall circuit is unlikely to have a response down to DC, and a coupling capacitor is storing energy, then releasing it back in the tail at the end of the waveform. An amp with capacitor coupled speaker output can show similar DC offset in the speaker drive, in comparison with a direct coupled output. If you consider the energy content shown by the areas under the curves (power), I'd guess the energy missing from the smaller amplitude initial half-cycle (being held in a capacitor rather than being delivered to load) looks pretty similar to the area under the tail (charge drained from the capacitor by load in the absence of further input, to return to zero potential).
disapointing result indeed, but in a more engineering way, it should make a difference. high class amplifiers these days in care audio have around 1000 factor, previous models were about 400, talking about brands like Helix, Zapco, etc. BUT too high damping factor it's not a good thing also. basically we need as much clean power we can get and good electronics circuits design
I thought AB had higher damping factor vs D? I guess not? All these guys been running AB on subs because damping factor and blah blah blah. I was headed that way too looking at C one amps.
You're not interested in the comments you only want us to comment because it helps the algorithm that way you get more views that way you can make more money off of this . at least be honest
Yes, you are absolutely right! Comments likes and shares indeed push the content to other people watching UA-cam as the algorithm is designed that way. Thank you for commenting and making me rich😉
@goditomi92 honesty? Is honesty to much to ask for? I guess so. See this world has gone to sh!t and people CANNOT be ohnest anymore everyone lies not a single ohnest person except me can be found in this rotten world
The cone always has overshoot. The lower the damping factor the less the overshoot. Likewise the cabinet can cause overshoot as well. If you have a low DF ina freely ported woofer it will overshoot and ring.
"Not totally scietific," but, as for your efforts, it's absolutely scientific.
Its truely amazing how much bs narratives and sneaky marketing affect the audio industry (all markets I suppose). I find it remarkable how people just parrot Social Media myths like its scientific fact.
It just takes one Influencer to mention something relatively believable, and it becomes the new standard. People seem to forget that most of these people are financially motivated to keep you watching and/or buying.
Thank you for keeping it real, and sharing what you learned 👊.
Than you for a good video! Something I understood after many years was that the speaker sees the damping factor as a series resistance of the output impedance of the power stage and the resistance of the speaker cable. Say the output impedance is 0.02 ohms gives 8/0.02=400. If we have a short or thick cable, it doesn't matter. resistance in copper 0.0175 ohm mm2/m. i.e. if you have 1 m of 2.5 mm2 i.e. 14 gauge it gives 0.007 ×2 ohms. 8/0.034=235. But if you have 5 m of 0.75mm2 i.e. 19 gauge (which is more common with midrange and treble as they don't have to cope with so much power) gives 0.116x2ohm. This gives 8/0.252=31. Then it doesn't matter with 400 or 2000 in damping factor because the cable accounts for all the resistance. Would be interesting to test different cable lengths.
Great testing. I think you need to compare the input and output signal. You can do this by subtracting the one signal from the other in audacity. If there is a difference in draping factor, you would see different peaks of the difference.
Great info. Thank you for taking the time to complete this experiment for us!
You need a tube amp with a crazy low damping factor of like *4* to see it become an issue. But, good video, good experiment, keep the science coming!
Thanks for schooling us to worry about the things that really matter in car audio.
Thank you! now I will now not to worry about having the highest possible damping factor amp :)
Put a 2 ohm resistor in series with woofer. You should plainly see the overshoot and ringing increase
Maybe disappointingly similar results, but helpful testing nonetheless.
Another interesting research topic related to output impedance of amplifiers and their ability to control the speaker cone would be voltage drive vs. current drive.
I've read some anecdotal evidence and couple research papers from those who have experimented with current-driven speakers, would be cool see more of unbiased testing and objective data to see if there's some truth to the alleged benefits of current-drive amplifiers
I've owned some really nice class AB amps over the years from ARC audio, Precision Power, Zapco c2k/ Reference..Some of these amps are now highly regarded and have some of that old school SQ mythos from the 90's/ early 2000's. I've used these amps with anywhere between 300-500 watts of rated output on some very nice subwoofers . Bottom line is these amps all had damping factors above 400 and up to 600 and costed sometimes $600-$1500 USD some 20 plus years ago( do the inflation calculations if you like). Today I'm using a $150 sub amp again on some really nice subwoofers and I can absolutely tell no difference.
glad to see my suspicions were true! great video
Long comment but relevant: These talking points or selling points about amp specifications from manufacturers all these years can be applied to multiple facets of sales in the industry from pushing or marketing these huge ofc power/ground cables for amplifier use, to "high end" RCA cables, to Sound deadener ( I could literally write an article about that market) among other things is just about larger sales/profit margins when they are mostly (not 100% cases but most for sure) total dimishing returns for the consumer/hobbyist. For just listening to music, sub amps that are capable of 2000 rms can still be connected with a 4 awg ofc power/ground and will be supplied with adequate voltage and current. Full range amps most certainly can be powered with 8 awg ofc almost always (yes OFC is better than CCA at least they get that right). These overkill situations with 2/0 awg plus are needed really for the guys that do the DB drags and I think for some cases that's overkill too. For the most part the companies try to sell you wire that is $5.00-$10/ft instead of $1/foot because it helps their profit margins (nothing more).
The same can be said all these years about sound deadening material and let me tell you having been in this hobby for 25 years I have spent my fair $hare of money on that $tuff which only added more weight to my car, made my bank account shrink, and made my door panels or roof have a solid sound when tapping on it instead of a ringing sound ( wow how useful).
The past two systems I have installed I have not used hardly any of that stuff except for maybe here or there to act as a decoupler for surfaces that needed some isolation to keep from pressing together. These last two setups have had the least amount of rattles out of all my others.
What makes the most difference for eliminating rattles in a car stereo designed for quality sound playback is not sound deadener treatmnent but knowing a few things about midbass/subwoofer integration. Most guys cross their sub LPF's way too high (@80-120 HZ) and the same for their midbasses. That's mostly where these rattles and buzzes are coming from. Too much energy in the (80-150 HZ) areas. Subs aren't supposed to be midbasses. The best thing a fellow can do to clean up rattles and buzzes is to use a solid baffle ( wood or high density plastic) for the midbass with a weather stripping type material behind it when screwed to the metal inner door and keeping their crossover points for their sub/ midbass around 50-70 HZ LPF/HPF 24DB. Depending on how loud you listen while it might not totally eliminate buzzes and rattlles it most certainly will reduce them far more than any amount of overpriced sound deader material you add to the car. Try it out and you also might find that it helps to eliminate sub localization.
This is very interesting
I have always wondered about the Schitt Aegir2 with a Damping Factor of “>10” which is the lowest I have ever seen
I don’t have one but the reviews are very positive and based on your testing that makes sense
🙏🙏🙏
Still doing the mythbusting work nobody else is doing online.
I remember in the 90's damping factor was a selling feature. In theory it matters, but in real world, apparently it doesn't. Even when I bought my current JL sub amps I saw the damping factor was 500 at 2 ohms and thought well, that's good. :)
in general, I agree with you. If you look from an acoustics point of view, there is no difference. but your graphs show differences in the factor. I think that if you connect a resistor instead of a speaker, the bottom graph will look more like the sound you are sending. I think that the peak after the end of the sound, and the graph of its fall, is the factor that we are looking for. this part of the graph is the electricity that returns from the speaker and the faster it becomes zero, the higher the damping factor
Interesting results, maybe we need more power or excursion to get an effect? It would also be interesting to have the same amp driven on different loads, and how that affects everything concerning damping factor. Therefore you might need a chassis in 4 and 2 Ohm, harder to do I know :)
The results from the mic measurement vs the electrical output from the amp should (at least in theory) lag about 90º from each other. The mic basically measures acceleration from the air in front of the cone, so the peaks of the mic values should align with the crossing points of the electrical input.
With other words, the peak from the mic reading should be aligned with the changing directions (or polarity) of the electrical sine wave. When there's maximum voltage from the amp on the top and bottom of the sine wave, there's no acceleration from the cone, so the mic reads "zero".
There's an awesome video of subwoofers by Alpha Sound about this subject.
I don't quite understand why all amps have such huge overshot at the end of any burst. Kind of wierd. The Stereophile magazine made similar experiment with very similar test signals to check speaker cables influence on speaker damping. And, as I recall, they captured overshoots at speaker terminals that were up to 2-3% of burst test signals in amplitude. But at the amp terminals those overshoots were next to zero.
("What a Difference a Wire Makes" by Ben Duncan | Jun 12, 2020 | First Published: Dec 1, 1995)
the overshoot comes from the dc blocking caps in the signal path of the amp. the charge up during the positive half wave and then even tho the signal goes to 0 and stays there they still have to discharge causing that overshoot. in other terms they introduce a phaseshift so the signal doesnt start on the same part of the wave and doesnt end on the same part so you dont completely end on 0
@@sedon7098 Isn't that overshoot a very high distortion then? Like 10-20% of the test signal? While typically modern amps have a distortion way less than 0.1%.
Distortion is measured using continuous waves where this overshoot would not be present. It's an artifact of using short test signals.
@@dwindeyerThis channel is devoted to testing of mobile audio equipment (“car audio”). Considering the outrageous amount of intentional distortion inherent in most music played in such systems, I think such artifacts would be buried in the very high road and engine noise when vehicles are actually in motion.
A note re the Visiton - it looks to be one of their “full-range” models very commonly used by home audio DIY builders, and would very often be high passed and reinforced with either passive or actively power woofers/subs at higher frequencies than used in this test. Not that this is intended to disparage the test, or dispute the results - indeed, i thought it performed rather well in comparison to purpose built drivers with substantially more powerful motors.
Nicely done, sir.
Would you mind sharing your raw audacity info. I am quite curious about cone control comparisons. And wha the effect of back emf might have on the results.
excellent job! I'm impressed. I have been wandering if I should Gor for a ridiculessly expensive JL Audio for the damping factor. Now I know
There are other reasons to go for JL stuff😉
I watch videos like yours to learn what i pay for. Would you be so kind and explain that when it comes to JL electronics, please? Thank you!!!
@@paul7000 It has to do with reliability and cleanliness. JL amp will last you ages, probably longer than the car. If you are planning in upgrading, that might not be of any benefit to you. But if you want an amp that will never cause you any problems,a JL or any other big brand will.be solid.
@@RAW-CAt you must be right, raw-cat, but it all seems like marketing bullish*t until I see test results. That's why I am turning my attention to your unbelievably useful videos like this one, where we can measure what is worth paying for. Without test like you do it all looks like a promise or voodoo marketing. How can we know that what they say is true without testing? I appreciate your videos and I am waiting for next videos to come.
So as far as I understand, every speakers has output a half cicle more than the one contained in the input signal, right? So the woofer are producing big distortion of the signal they have to reproduce. I did not expect that! How would perform a smalles driver live the ones currently used by many hi fi tower speakers manufacturers? Let say a 6,5 “ or 5,5”? Have you ever tested such drivers? Thank you and congratulations for your video!
You mention driving the speakers with 3 to 7 volts. Did you try more voltage/output?
Yes, in free air they go over Xmax. And the smaller amp cannot drive the HDZ sub with more power.
@@RAW-CAt I see, maybe build an enclosure for the smaller driver and run it to max unclipped output of the weakest amp, then compare with other amps at same voltage? Thank you so much for your effort and exploration, I just feel like there must be a way to measure this more accurately.
Interesting Test, thank you! Have you verified what is coming out of the focusrite interface?
Instead of a rabbit hole, you hit bed rock.
@RAW-CAt- Ive been doing some research on how damping factor maters more as the freq. gets lower.Also how the resistance of the awg., & length of the speaker wire is usually why we can't hear the difference of a damping factor of 100 or @ the most 200. Example: the resistance of a 10ft, or roughly 3meter, 12 awg speaker cable can only pass a damping factor of 200. So smaller gauge, or longer cables would restrict more. I would like to see a 4 gauge cable, approximately 3ft, or 1meter long, wired to a 4 ohm woofer, @ 10 Hz, to see how much a damping factor of 100, 200, 400, & even 1,000 might change the detail, & impact of that freq.!? I have in my Large SUV, 4-Fi built D2 18s(with 33mm of X Max, & 3,500 r.m.s. 4 inch coils), in about a 850 Liters/30 cu. Ft. ported enclosure, tuned way low! Powered by a 17k amp. My wiring options would be .25= not going to try for this test, 1 ohm, 4 ohms, or 16 ohms. My amp is rated with a damping factor of 400 @ 4 ohms, so @ .25 of an ohm👀yikes= a damping factor of only 25, 1 ohm= 100, 4 ohms= 400, & 16 ohms= 1,600! This would be a great test, but i am unable to because i am disabled, & have not been outside in almost 5 years!
Your case is very unique. The fact still remains that for 99.9% of people the damping factor has absolutely no influence.
Would dampening factor change when put into an enclosure? IE ported, sealed, IB, and bandpass enclosures.
You should really test the Sony XM- GS4. It’s said to be the best budget sq amp for mids and highs. I wonder how true that really is.
Can you measure the amp playing into a resistive load too?
Measure what exactly?
@@RAW-CAt the output signal when playing the same sections of sine waves. It'd be interesting to see if they still have that overshoot with a non-inductive load
Love this channel
One thing about it💁 ive never had a great amp without high damping.. ive never had a good amp with low damping .. and ive never had a bad amp high damping.. and i dont think anyone else has either... So it seems to me damping even at minimum shows use of quality parts and design go hand and hand and generally result a good df rather deemed useful or not..
i would agree based off of equipment i have owned.
Recording the amp output with a speaker connected means you're recording the amp + Back EMF of the driver, not just the amp itself. Or am I missing something?
Hi friend! I hope you can give me your opinion. I was using an audison bitone.1 and then it went to valhalla. Now i need a new DSP. My options here are Helix mini dsp and alpine pxe-0850x for similar price. Any other option is way over my budget. I run a morel hybrid ovation 6 2way kit and a jl 10w6v2, so i dont really need more than 6 channels. The car is a ford fusion with sync 3. Which one would you choose between the Alpine and Helix? Thanks man!!! Very nice channel!!!
If 6 channels is enough, go with the Helix. It will be smaller and easier to install. However for having a future proof system with possibility to upgrade, I would choose the Alpine with more channels.
Nerijus I have a comment/question about the last statement you made in this video. You suggest when picking an amplifier to generally choose one that’s the cleanest AND has the most power. I get that but what has me confused is that in just about all of the distortion graphs you’ve posted of different amplifiers you’ve tested, the least amount of THD present is generally just below rated power of the amplifier. Right before it jumps way up into clipping.
I may be reading the graphs wrong but the general trend in most of them is a downward trend in THD as the power output goes up to a certain level and then a sharp rise as the amp reaches full output power.
In that case would it make more sense to choose an amplifier with lower power output for driving midrange and tweeters? Especially if you listen at moderate levels somewhere around 90db? I know there’s drivers out there that can play that level, and some slightly above, with just 1watt of power.
So even accounting for good headroom would an amplifier that outputs around 30-40 watts at its lowest THD be a better choice than a more powerful amp that has its lowest THD at around 90-100 watts? I’m talking about just for midrange and tweeters. And I’m just using those wattages as an example. I have no clue what real world wattages would be to drive midranges and tweeters to a modest listening level while still maintaining adequate headroom for dynamic peaks.
Thanks for all your hard work putting out these videos.
Yes, you are absolutely correct. An amplifier with less rated power might be cleaner than a more powerful one at lower wattage. However, that is mainly THD+N. For a lot of amplifiers THD is a straight line and shoots up only before clipping. Noise is the thing that raises the curve at lower power levels. However, if the noise is very low and is not audible, it does not matter much. The problem is that these days there are not many low power amplifiers. You can fing old school 4x30W, but not today..
@@RAW-CAt Thanks for clearing that up for me. I actually have an old school MTX 4320 Thunder series amp that I bought new back in 1994 I think. It’s rated at 4x40 but the birthsheet actually shows a lot more. It’s a very clean amp and was a direct competitor to the old Alpines that you use. Mark Eldridge actually won several world competitions using these amps in his early 4 Runner builds.
I have been using it since then up until recently when it started to pick up some alternator whine.. I switched it out to a JL HD600 and it’s way too much power for what I’m using it for and just doesn’t sound as clean as the old MTX. If I didn’t live in the US I would ship it to you for testing. I’m pretty confident it would measure every bit as good as your Alpines.
excellent, as always.
the problem is with the traditional drivers. electrostatics may be superior /more accurate due to much lighter construction.
I strongly encourage you to bandpass filter that output. You think you have only 40Hz, but you don’t. Those sharp edges of the waveform at the start and end of it have energy at other frequencies- high frequencies.
Think of it this way. Anything that changes in time faster than your smooth sine wave - any turns in that wave faster than what you see in your sine wave- means there are higher frequency components in there. Going from flat to suddenly starting into the sine wave has that. Ditto on the end of it. Stopping on a dime needs a fast rate of change - aka a high frequency.
I'm not sure why my previous comment got deleted. Perhaps b/c I included links in it. But, the quick version was that you can take your single cycle from REW, save it as a WAV and in Audacity, select that bit and copy/paste it to the middle of your 1.3s or so clip (or just pad the beginning with silence.). Then, analyze, plot spectrum. You'll see a massive amount of high frequency energy in there. If you run the Generator, CEA-2010 in REW to make it, you'll see far less.
Next, though, just run both a high-pass and a low-pass filter on your sample -- say high-pass at 20Hz and low-pass at 80 Hz with a steep cut. The same plot spectrum will show the effect as you're now far closer to just having energy at 40 Hz.
Finally, try something in REW like square wave, 1Hz, duty cycle 1%, and a 3s duration to make a WAV that has clicks at 1Hz. Super low right? Plot the spectrum of that (just select one if you like) and you'll see an almost linear decay that goes all the way out to the highest frequencies. Making that sharp transient of a square wave actually has energy at all sample-able frequencies.
I wonder if the damping factor myth will ever go away? BTW, I have repeated this elsewhere, but make a loudspeaker draw the same current from LF to 100KHz (current EQ) and the speaker will always behave like it sees a zero Ohm output impedance from the amplifier. *_Any_* amplifier! You can now even use a fairly high output impedance tube amplifier and it will still look like zero Ohm. No, I am not kidding because I am listening to this right now.
You should have also tested the cables and termination as they have resistive values and can negate any damping factor of an amp. So if you habe an amp with a DF of 500 and another with 25, but use terrible cables ans high mass termination, you can bring both damoing factors to almost the same.
For instance, the amp of a DF of 500 lets assume that is at 8 ohms. 8÷500=0.016 output impedance.
The amp of a DF of 25 has an output impedance of 0.32.
Now lets use 2 different resistive values for speaker cables. Lets use .250 ohms and .00350 ohms.
The amps with a DF of 500.
.016+.250 = .266 which to find out the DF of thst outout impedance lets keep it at 8 ohms. 8÷.266 = 30 DF.
Now lets try that with the .00350 cable. .016+.00350=.0195 which is a df of 410.
Now lets try the amp of a DF of 25
.32+.250 = .57 which is. DF of 14. And for the other cable. .32 + .00350=.3235 which is a DF of 24.72.
You see how much cables and termination can negate the DF of a higher DF amp. With the high resistance cables, both amps would sound the same with the bass. This is also why a lot of people think all amps sound the same. Their cables can be negating the differences in DF.
All measurements were done with very short oversized cables, so resistance is minimal. Off camera I compared those measurements with an 8 meter long cable that has higher resistance, however there were 0 difference between the measurements..
All true. And all irrelevant. The DC resistance of the voice coil is in series with all the other resistances. The DC resistance of the voice coil is typically about 60-70% of the rated impedance of a cone speaker. Lets say 5 ohms for an 8 ohm speaker. A few milliohms of cable resitance or connection resistance is a rounding error. The amount of electrical damping the loadspeaker experiences is totally dominated by its own resistance, unless the amplifiers output impedance is measures in ohms, not milliohms.
@@RAW-CAt Please check the Sterophile article "What a Difference a Wire Makes" by Ben Duncan | Jun 12, 2020 | First Published: Dec 1, 1995.
@@RAW-CAt Please check the Stereophile article "What a Difference a Wire Makes" by Ben Duncan Jun 12, 2020
@@RAW-CAtcables that I saw in the video were relatively thin. Plus, crocodile clips can have high contact resistance. Unless this wasn't the test setup actually used?
Well 40hz free air is pretty hard to hear, wouldnt ih be different when an driver is mountet in an enclosure and measure in the port (if portet enclosure) or better measure the pressure in the cabinet.
Of course it would be different. However the purpose of the test is to see how the amplifier "controls" the driver. Not a system with acoustic air suspension or port resonances, only the driver itself.
@RAW-CAt thats also My point.
You are measuring the driver in free air with a mic thats designet to measure sound.
Most subs don't play 40hz or it barely to hear free air. If you put it in an enclosure in a car, you got cabin gain and also the output from the driver in the cabinet. Here it should be a lot easier for Even the mic to measure or Else if you measure the pressure or with the mic in the port, it should be a lot easier to pick up for an mic.
I think you need a low-pass after the Focusrite Interface. The burst you are generating contains high frequeny, this is why the speakers behave so different from the electrical Signal. I think it's quite rediculous to evaluate a result more than relative.
The waveform is a sine wave, which contains only the fundamental frequency - where are you finding high frequency?
@@PlatypusPerspective hi, at the beginning and the end if you want. Zero line to sine transition ist like a transition, different to a contiuous sine. This is why I think a low pass would Help. Do you agree that what the Amp outputs is very different to your sine? It is the sidebands being added by turning the sine ON and off. Does that make any sense?
Visually the high frequencies are in the sharp corner between the Zero line and the ascending sine. IT is almost like a rectangle.
@@thomasschwarzenberger8943 Hi there, we'd need to see the waveform at the input of the amp to be sure how closely it is able to follow it. We're taking it on trust that REW is creating an ideal waveform, and that the DAC is outputting it faithfully.
It seems likely it is, at least at the start of the sine wave which looks extremely good to me, I can't see any hint of a discontinuity there, it seems pretty much exactly as it would be if it was the zero crossing to the second half-cycle if there had been a negative swing preceding it. Have you noticed that the subsequent divergence of the wave is due to developing a DC offset? The discontinuity at the end is the waveform terminating at the correct time but pushed off the zero value by the offset amount. Again, we'd need to compare the different stages of signal processing to see where this originates. It relates to reactive energy storage in the signal path, and several people have requested comparative tests into a purely resistive load to see how much of the variance is due to the speaker's reactance. If we could observe either that a resistive load resulted in the theoretically correct waveform at the amp output, or that the amp input signal is in fact the exact theoretical REW waveform, implying the same thing, we could form a better conclusion.
@@PlatypusPerspective I saw that, and was thinking this looks Like a coupling capacitor being discharged. Speaker ground, Signal ground and supply ground are the same? Could it be that the Amp causes just a ground shift?
@@thomasschwarzenberger8943 Yes, my initial thought was the overall circuit is unlikely to have a response down to DC, and a coupling capacitor is storing energy, then releasing it back in the tail at the end of the waveform. An amp with capacitor coupled speaker output can show similar DC offset in the speaker drive, in comparison with a direct coupled output. If you consider the energy content shown by the areas under the curves (power), I'd guess the energy missing from the smaller amplitude initial half-cycle (being held in a capacitor rather than being delivered to load) looks pretty similar to the area under the tail (charge drained from the capacitor by load in the absence of further input, to return to zero potential).
disapointing result indeed, but in a more engineering way, it should make a difference. high class amplifiers these days in care audio have around 1000 factor, previous models were about 400, talking about brands like Helix, Zapco, etc. BUT too high damping factor it's not a good thing also. basically we need as much clean power we can get and good electronics circuits design
I think the only way youre gonna see a difference is with very very low damping factors which are seemingly hard to find.
im pretty sure older main stream class AB amps had lower damping factor. late 90s 2000s.
when class D amps 1st came out i couldnt stand them. they were garbage.
You shouldn't place one equipment over the other. The metal bodies shouldn't touch to make some loops
Well alp equipment is sharing the same ground anyway. Not sure about what loops you are talking about...
@@RAW-CAt inter equipment gnd loops
I thought AB had higher damping factor vs D? I guess not? All these guys been running AB on subs because damping factor and blah blah blah. I was headed that way too looking at C one amps.
Maybe some AB have higher damping factor🤷 Maybe Alpine class D amps are just above the rest.
i think it shows
You're not interested in the comments you only want us to comment because it helps the algorithm that way you get more views that way you can make more money off of this . at least be honest
Yes, you are absolutely right! Comments likes and shares indeed push the content to other people watching UA-cam as the algorithm is designed that way. Thank you for commenting and making me rich😉
Nerijus puts so much work, time and effort in his content. We can watch it free of charge. Is it too much to ask?! 🤔 Don't think so!
@goditomi92 honesty? Is honesty to much to ask for? I guess so. See this world has gone to sh!t and people CANNOT be ohnest anymore everyone lies not a single ohnest person except me can be found in this rotten world
@RAW-CAt you don't disagree with me see what a sh!tty world we live in
@@SheikhN-bible-syndrome if you cannot pick up sarcasm, that is your problem.
The cone always has overshoot. The lower the damping factor the less the overshoot. Likewise the cabinet can cause overshoot as well. If you have a low DF ina freely ported woofer it will overshoot and ring.