Harmonic Distortion is overrated.

Some Resources:
Purifi Demo:
purifi-audio.com/2019/12/07/a...
KLIPPEL Presentation:
www.klippel.de/fileadmin/klip...
Timestamps:
8:07 - Harmonic Distortion
16:20 - Intermodulated Distortion
27:33 - Multitone Distortion
30:36 - Multitone Comparison at 96dB/1m
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____________________
All of my tests are conducted using KLIPPEL Hardware and Software. KLIPPEL is an innovative leader in providing unique test equipment for electro-acoustical transducers and audio systems. Founded in 1997 by Dr. Wolfgang Klippel, the novel techniques developed for control and measurement systems of loudspeakers and other transducers are the result of over 30 years of fundamental research. This provides more accurate physical models of loudspeakers, micro-speakers and headphones valid for both small and large amplitudes. The focus is on revealing the root causes of signal distortion and defects and giving practical indications for improvements in design and manufacturing of audio products. For information on KLIPPEL products, please visit their site below:
www.klippel.de/company/about-u...

[@mixxeerr]

Love this. Thanks for educating us hobbyists. The more I learn about the science of audio the more I understand how much BS there is from the ultra high end HiFi. All those jokers never publish objective data and/or too scared to let objective reviewers have a crack at their $100k speakers.

[@pabloherman8836]

I love your videos! You and Amir are the only two doing SERIOUS reviews and tutorials. Thank you for the effort.

[@joshmelo605]

Excellent content again Erin!

[@juicebox853]

You always provide interesting content. Very educational for us hobbyists. Thanks Erin.

[@ErinsAudioCorner]

I appreciate that!

[@gameswong]

Erin, Thank you so much for this video. We have seen tons of review video. This is the first video not only with a lot of information but also with audio example. Please make more video like these to educate the community to how to listen and be able to relate the objective data to the subjective listening experience. Thank you so much again to make such a complicated subject very easy to understand. Great work!!!

[@rustygates3367]

Great stuff Erin, well put together as usual!

[@ErinsAudioCorner]

Glad you enjoyed it!

[@Saturn2888]

Your newer videos have improved so much! This one's super wordy.

[@tee-jaythestereo-bargainph2120]

Great Job Erin , I APPRICATE THE HARD WORK AND DEDICATION you share with us on your channel !

[@ErinsAudioCorner]

Thanks!

[@boydrijkvan6500]

Thank you for this fantastic video!! I have learned a lot, which was a surprise for sure. Great that you will include the multi-tone distortion testing again.

[@erics.4113]

I'm still a little shaky on the different distortion types, but no doubt this was packed with useful information and caused a number of lightbulb moments for me. I've consumed plenty of gear reviews and it's high time I educate myself further on the actual science behind these components!

[@ErinsAudioCorner]

Well, I'm glad to hear the video was at least somewhat helpful. That's the goal.

[@sawcp]

Finally, someone making a "hearing experience vs data correlation" video. This really makes the importance of data come to live and also educate us on which data matters. Thanks, bro!

[@idray986]

This is awesome, very easy to hear through a THX Onyx paired with Sennheiser 599. Thank you Erin

[@ErinsAudioCorner]

Great! Glad it's helpful!

[@Clobercow1]

Erin, this is some seriously top notch content and I'm glad you're doing it. Gona sub on patreon right now.

[@carywatson1146]

Really well done! Got your passion for sure! So appreciate you.

[@ErinsAudioCorner]

I appreciate that!

[@TheReverendSlim]

Late to the party, but great video, Erin! It helped me wrap my head around what the measurements you post in your reviews represent. Good stuff.

[@dilbyjones]

Glad u are here man, this distortion stuff is above my pay grade. Einstein says when u UNDERSTAND something well u can explain it easily & simply.

[@EngineeringEssentials]

You have done great work at explaining these complex technical terms. I can't thank you enough for your contribution to my learning journey. In future, I would like to see a detailed video on Amplitude and frequency modulation in loudspeakers. Thank you for the video again!.

[@ErinsAudioCorner]

Thanks. Make sure to check out the Purifi link in the description. It is a great breakdown and has some samples of the two. 👍

[@EngineeringEssentials]

@@ErinsAudioCorner Sure, Thanks alot.

[@davehill9951]

A stack of marshall 4x12 cabinets and a 100 watt head with a Jackson guitar makes amazin distortion!

[@st170ish]

Thanks Erin cleared up a lot of info/reasons crits you give in your measurements that I failed to understand the meanings of.

[@ErinsAudioCorner]

Glad to hear that.

[@iarwa1n635]

How come this only has 8k views is baffling to me. Very educational video, thx.

[@59seank]

Erin, your dedication to teaching us is amazing. Does your family miss you. ;)

[@SDX9000]

Thank you for providing this video - super valuable :)

[@JosephCrowesDIYSpeakerBuilding]

Excellent video! I’ve found that even microphones have a hard time with multitone, and can sometimes become a bottleneck when trying to design an ultra low distortion speaker.

[@raffima355]

Very jnteresting video! Whats the cause for the compression? Is it thermal compression? 22v is a lot for a voice cool this small but it seems still weird to me that such a short stimulus would be enough to achieve such a high compression

[@AmazonasBiotop]

Thank you Erin. Got better understanding of why more precisely it is good/benefits to high pass. I have small magnapan that roll off at 53 Hz and I crossed over to the left and right bass woofers there. And when doing A/B comparison with a box speaker and magnapan I noticed that the box speaker sounding better at ~80 Hz. When the bass woofers that I have can play to ~2 kHz. So I decided to move the crossover point from 53 to 100 Hz. And that is no problem for the woofers and I have two of them in stereo configuration and somewhat behind the mains so directionality is no issue. Now the A/B comparison showed no benefit in this areas for the box speaker. And all the other areas there were the magnapan already better. But now I understand that I have done a huge favor to increase the SQ by hi pass and remove the lowest frequencies from the mains. Thanks Erin! 🥰

[@ErinsAudioCorner]

Awesome, man! Glad to hear that!

[@adamjj85]

Great work Erin! Love the explanation. How about a part 2 on why harmonic distortion is supposed to be pleasurable to listen to and how tube amps affect distortion levels in a speaker?

[@ErinsAudioCorner]

Thanks. I might have to leave that video to someone else. I'm spent. LOL

[@phpn99]

Thank you so much, Erin ! This is GOOD.

[@ErinsAudioCorner]

So glad!

[@sudd3660]

i got a deal on some 3" full range drivers, i tested them individually and with music, to get them to sound good i had to cross them over at 200hz and have two of them in MTM configuration. those where scanspeak drivers and had more excursion than i expected but not usage since there was distortion.

[@rigorhead01]

Harmonic distortion can actually be quite pleasing to the ear. They may or may not realize what is actually going on, but most guitar players use overdrive and distortion effects because it's more pleasing to listen to, and the compression and interaction between the fingers, guitar strings, and speaker creates this symbiotic relationship that is perceived as magic by the guitarist. This is why ALL high-end guitar amps are tube amps. The tubes distort in a very pleasing, musical way. ie they produce harmonic distortion when overdriven. It's all very fascinating (to me anyways!).

[@ErinsAudioCorner]

Yes, I've heard this as well. I love me some 80's synth music which uses various forms of distortion to create the sounds.

[@sub-jec-tiv]

Not all high end guitar amps are tube. One of the most beloved amps in the world is the Roland Jazz Chorus, as used by The Cure and many others. It’s great with pedals, it’s very pretty and clean sounding. No tubes.

[@citronski]

I think we should note that that distortion is part of the creative expression of the artist/sound engineer. I don't want my speakers or amp to add distortion because it wasn't intended to be there.

[@broadneydangerfield]

Hey Erin! Appreciate all that you do for us. Would you say that, in general, listening at around 70 dB would be ideal, a bit lower, or another level? Of course, selecting monitors with less distortion, using a 3-way system, or a 2-way with sub will help, but I'm just wondering if there is a decibel level you personally feel provides minimal distortion while still allowing all elements of a song to be heard with high clarity. Thanks for your time!

[@stephenwhite5444]

Excellent education bro!

[@dannyrichie9743]

Good video.

[@ErinsAudioCorner]

Thanks, Danny.

[@johnwet6969]

I have a question but firstly I want to say that you are the Most useful guy in YT in speaker area. Thanks a lot for your work! Serious and logical technical information and real experiences instead of tons of marketing BS, snake oils, kryogenic whatever and pretended emotions. After many hours of studying and reading and listening not only your channel I’m still little bit confused about speaker type for my small room. Around 12x16” In term of multi tone distortion does it mean that I always need 3-way speakers or 2-way bookshelves with nice sub? Does it mean that 2-way bookshelves alone are not able to play without this harshness and distortion? Or in some cases and levels up to 85-90 db it can be fine? I’m thinking about changing my passive floorstanders with active studio monitors of high quality. But I’m not sure what will be better choice for me, regardless of the price. For example Neumann KH150 vs Focal Trio 11be. Or maybe passive like Dynaudio Heritage vs Wharfedale Dovedale. (I hope you will test Dovedale soon 🤓 )

[@dan-qe1tb]

Good video. Let's face it, many folks haven't been trained in electrical engineering, or physics, or acoustics. People can still learn about it online. The knowledge of someone like Alan Lofft at Canada's Axiom, was useful to me: there's a publicized study out there showing the degree to which the music is masking THD. Key points: 1. Distortion is measurable, but often not audible when we look at how those measurements relate to real world music and not pure test tones, as music has fundamentals and overtones. Music doesn't consist of pure tones. 2. Detectability in terms of what your brain is processing, and not a machine, deteriorates when we lower the frequency. Myself, after using REW for a length of time, I had experienced first hand how much sub 200 Hz sound changes simply by moving the speakers or my listening position, enough to make me ignore most FR and THD graphs below that frequency I see online. I can see a lot of speaker comparisons online (which I now ignore), graph 'x' shows a high Q THD spike to 3.5% at a certain frequency, and is labelled "worrisome" compared to graph 'y' which is 1%. Those people, need to read the Axiom study. At the price level I look at, I would only seek confirmation that the $2000 speakers have lower distortion and can play louder than the $400 speakers. Your DAC and amp isn't adding an appreciable amount of distortion, in most people's systems, yet on the same site, I see fifty or more Chinese DACs, ranked by SINAD. I pay the most attention to how the distortion rises with volume with a given speaker (like, "what would be the right size of speaker for my listening area"?): 90 db in close proximity falls off rapidly if I'm in the adjacent room.

[@matthewhilty4209]

Does Altitude , temperature and humidity also affect dB measurements at different distances ? Or do you think that these influences are negligible ? I always assumed my system sounded better at night because of the lower background noise but maybe temperature and humidity is also a factor.

[@picassoimpaler3243]

Now that I know what multi tone distortion is, and how to read the data, I would love to see it up again. Even if you have some of the drivers you've already done (like the purifi) I would love to have the old ones updated. Thanks for all the info as always!

[@ErinsAudioCorner]

I'll try to re-test those drivers again since Purifi told me to keep them. Not sure when I'll get to it, though, because that requires a different setup.

[@picassoimpaler3243]

@@ErinsAudioCorneryou're the one doing all the work, so we are on your time man! Now that it is explicit as to the difference, I see why it interests you.

[@leon7087]

Great Video. I think the multitone distortion is a great Addition could you tell which frequencies you play? I would love to know more about phase and time domaine if you could make a video about that maybe the aufibility of resonances and Mixed Phase. That would be super cool

[@ErinsAudioCorner]

I think Rene is going to help us all with phase. Not sure when we'll be able to make the video but hopefully it'll be relatively soon.

[@maxpower7504]

Erin this was my favourite so far. Keep it up man. Do you think you could provide the multi tone as an FFT graph in addition to the percentage/db y scale graph. Would be interesting to compare multi tone distortion profiles across speakers as they will all “behave” differently in this way compared to just seeing the overall percentage. No drama if not, any data is good data. Do you think that multi tone distortion is just a sum of multiple IMDs being excited all at once?

[@ErinsAudioCorner]

I’ll try to do that.

[@coolkingakram.]

Great video but can you please tell us what driver your are testing so we can contextualize those numbers?

[@DougMen1]

IM distortion and odd order THD are much more audible (and annoying) than even order THD, because they have no pitch relationship to the original tone, where even order tones are always just octaves of the original tone. I urge everyone to go to the RMAF YT channel and watch the lecture from a guy from Audio Precision, the company that makes much of the test equipment that everyone uses to test electronics and speakers. It's quite illuminating how high the levels of distortion have to be before they are clearly audible to the audience, who are all industry pros that have more experience with critical listening (ostensibly) than the average person off the street. His demonstration also shows that in some cases the distortion is much more audible at lower levels than in others depending on the type of distortion

[@ErinsAudioCorner]

I've seen that presentation at least 2x. It is indeed great. Until the doofus at the end shows up trying to act like he knows everything and the lecturer lets him down easily. 😅

[@RennieAsh]

@@ErinsAudioCorner there's a song for him kzbin.info/www/bejne/qKDaYX2mZdyfhac

[@DougMen1]

@@ErinsAudioCorner Hahaha! He even admits that he forgets how to setup and operate his Audio Precision equipment, lol

[@DougMen1]

@@ErinsAudioCorner Another great lecture at the RMAF YT channel is JA talking about speaker measurements. He has arguably measured more speakers, from budget level to those that cost as much as a house, over several decades, than anyone else on the planet

[@ShamuXEagleDriver]

Erin, Great work, very eye opening. Is there anyway to add a bookmark of some kind to the video at the test tone starts; 8:08 (harmonic), 16:20 (intermodulation), 27:33 (multi tonal) and 30:36 (multi compare)? Easily revisiting/listening at these points would be even more helpful. Cheers, XEagleDriver

[@ShamuXEagleDriver]

Holy crap, it just did it in the comment, at least on my Android phone, too cool. Hope others see the same functionality 🙂

[@ErinsAudioCorner]

haha! Yea, I'll take your time stamps and add them to the video. Thanks for doing God's work. 😂

[@cbrunhaver]

You’re doing a great job Erin

[@ErinsAudioCorner]

Thanks, Chris(?). 🙂

[@cbrunhaver]

@@ErinsAudioCorner yup, it’s me 🙂

[@ErinsAudioCorner]

@@cbrunhaver ha! Now I will stalk your internet profile!!!! Muahahahaha. 🤪

[@mysock351C]

Wish I had seen this video earlier 😀. One Q: Is the "voice mic" only providing the audio, while the measurement mic provides the measurement? I ask as if we are not measuring the voice mic, then we have no idea what the actual distortion is since those microphones can crater at high SPLs and generate loads of distortion on their own, i.e. the measurement microphone and speaker can be hunky-dory, but the voice distorting heavily in the audio that we hear. Edit: I assume it is being analyzed as well from a quick waterfall plot of the audio matching roughly what's on the Klippel screens, but I wasn't 100% clear on what's being measured.

[@Oneminde]

Do you have a general idea of which type of diaphragm type which generally handles multitones better - a well designed paper or hard material ?

[@rynev3392]

Generally speaking in your experience, is slightly above the natural roll-off point of a speaker a good point to set the crossover? Or much higher to minimize any chances of distortion at high volumes

[@ErinsAudioCorner]

It depends on what the purpose is. Generally speaking, I'd stay far away from Fs of the driver unless it's a subwoofer or meant to be ran full-range (like a ported speaker, etc). In the latter two cases, I'd just use caution with the volume and let mechanical noise (like the woofer plopping) or audible distortion tell me if I'm pushing it too hard. Basically, just using some common sense with those cases.

[@MichaelBeeny]

That unit is really a very expensive mid range unit, it's quite fair from 200Hz to about 1.5kKz on a good day.

[@backrack01]

Thank u for this:)

[@ErinsAudioCorner]

You're welcome 😊

[@tetradkepler3091]

Great work! Thank you so much. You are mostly dealing with the dynamic speaker units. By their shape of a cone, 2nd harmonic distortion is always dominant. If you measure the distortion characteristic of an electrostatic or even that of a magnaplanar ribbon, the 3rd harmonic may be even greater than the 2nd harmonics. Overall, we know that the planars are limited by the smaller dynamic range. Yet, it may show much better distortion characteristics. IMD comes from the compressed motion of the cone structure at high excursion. If so, the electrostatic may turn out to be much better than that of a dynamic speaker unit. That is my wild guess. Have you ever measured the distortion characteristics of planar speakers? Electronstatic, e.g. quad ESL63, and big ribbons e.g., any Magnaplanar model,

[@RennieAsh]

Aren't Maggie's called something else, being a flat coil/strands on a membrane? Whereas ribbon is a single membrane of conductive material

[@jeffsloane8628]

The more I get into audio and the more I watch videos like this the more I want to hear coax open baffle speakers. Like the Andrew Jones, TAD, KEF stuff, but with like an 8" mid range, coaxial mounted tweeter in an open baffle setup, possibly paired with some type of subwoofer system to handle bass from 10 to say 50 Hz. Also we need an industry standard for inter modulated distortion output in loud speakers as this would go along way to identify speakers with output issues.

[@BastianUllr]

Guys - is it worth comparing IM distortion figures based on the material of the cone? If this has been done, are there papers about this? How much the self damping capabilities of the driver smoothens this issue out? Worth considering?

[@steakhoux]

Would it be possible to normalise the playback level of the test tones. So they are the same level when played back for the test. The test with the lower volumes are quieter and thus it is more difficult to judge distortion because of that. BTW that MD distortion at max voltage is really horrendous even at lower playback level. It just bite in my ears.

[@ErinsAudioCorner]

I wanted to but I decided against it because it would have been a bit of a chore given that compression is varied over frequency (in the multitone test).

[@CptMark]

How many tones did you use in your MTD test?

[@nicoras8803]

Nice demo to those who has been scratching their heads about distortion, You present 'n practical analysis that even the dumbest audiophile will understand. However, please also iterate the fact that distortion increases in level exponentially, while the test tone increases linearly with volume. A high power amplifier should be adopted to lay at relatively low value in Oder subdue the distortion at higher levels.

[@Novilicious]

Erin, is not true that the bigger the speaker the less it will distort when you play it full range? Did you want this test on the Atlantic technology 8600? Did it 8600s distort the same when you used full range vs high pass with sub?

[@ErinsAudioCorner]

That's unfortunately not always true. Generally, that's what you'd expect. But if the drivers don't have good linear excursion then they'll create distortion just like any other driver of any other size would. There are many little caveats to this stuff so that's why blanket statements rarely work.

[@Novilicious]

@@ErinsAudioCorner I’m going to check out your 8600 review again. I’ve always thought what Paul from PS Audio says and that is to run speakers full range for a better sound. Thank you for your work

[@JoelHernandez-tz3vk]

Wonder how much could this knowledge help in figuring out how to close the gap between budget and TOTL.

[@jamiet74]

Why did the Amir video disappear? I watched a few minutes of it and then it said it was unavailable

[@ErinsAudioCorner]

I just made a post about why.

[@johnraven5093]

So, adding a subwoofer can lower the distortion in a loudspeaker at some frequency ?

[@impuls60]

The highpass on the speaker itself lowers distortion. The sub is just to add back the the bass sound you just lost.

[@pliedtka]

Yeap. You limit the cone excursion and in the process reduce distortions. The way driver produces distortions depends on design: motor and it's design to linearize field, voice coil size (heat dissipation) and inductance, mechanical properties of the suspension, and of course cone itself. By keeping voice coil excursion limited one keeps it in linear field where it's strength is the highest. Keeping excursion low reduces the distortions produced by suspension which usually isn't linear. When ones look a the driver data from Klippel measurements done by Erin, the graphs show the relationships. Also hificompass has some excellent data.

[@davidcarr2216]

Excellent work Erin. There are lots of audio terms which are bandied around which I'm not sure about so this has been very useful. BTW the multitone distortion sounds like the soundtrack to some of those old Hammer horror movies.

[@user-dh7lt4we2t]

That's so much to consider when building a speaker... How to keep bass extension good, multi tone distortion low, wide constant directivity....

[@ErinsAudioCorner]

Absolutely. Designs are always a set of compromises.

[@user-dh7lt4we2t]

@@ErinsAudioCorner And I no longer dare to claim my diy speaker sounds great😂

[@ErinsAudioCorner]

@@user-dh7lt4we2t You’re not alone. This happens more and more as I listen to and test speakers. Not just DIY speakers, either. But I am hopeful that my results help the DIY community and understanding why some of their designs are far from what they expected. Typically, it can easily be boils down to their measurement methods. There are some really brilliant fellows making DIY designs and with a little bit more knowledge on how to properly measure them, those designs can be even better. 👍

[@octilliondollars]

It seems like one of the problems with IM and multitone measurements is the lack of standardized testing. I'm about to test quite a few different drivers and would like to incorporate IM and multitone testing but there are so many different methods that it seems like aside from comparing to my own other measurements, I can't use this data to compare with what someone else has done. It would be great if you could propose a standardized measurement that different people can do (using REW or similar software) in order to be able to share and compare data

[@ErinsAudioCorner]

I hear you. I don't think there's a standard because it's typically been for designers. So, they set the terms based on what they want to focus on. Having said that, KLIPPEL has suggestions on how to set it. For example, they might say to set the bass tone at Fs*0.5 and the Voice Tone(s) at Fs*(8, 20). I'd recommend checking out their website under "DIS" for application notes.

[@dgregory4178]

I have always been able to hear this while everyone I know doesn't have a clue. My wife would be listening to one of my bluetooth speakers and it's way over bounds into distortion and she simply can't hear it. She and my brother in law have the same penchant. They have blown up a couple speakers of mine in our business and i am perplexed as to why this can't be heard.

[@danielcomptonnz]

> In order to keep this video short Checks video length, sees 36 minutes 😃

[@ErinsAudioCorner]

Yea. I meant to edit that out. LOL

[@pascalmartin1891]

A two engines plane makes a very weird modulated noise, because of the slight frequency difference between the two engines. "Sounds" like an example of intermodular distortion?

[@ukspawn666]

so the more "ways" you split your drivers the better the distortion on all of them. eg 2way, 3 way, 4 way systems etc. mine is 4 way, 3way speakers and then subs

[@Sam785211578]

The amplitude modulation sounded a lot like ring modulations to me. Well, turns out its the same thing, but its intentional on the latter!

[@milesdufourny4813]

Yeah, I can see it plainly, it's on your T-Shirt!

[@ErinsAudioCorner]

How dare you!

[@VioletGiraffe]

I think I've heard that 3%single-tone distortion (as a change in the pitch), but not 100% sure because varying level makes it hard to tell. Wish all the recorded sounds were level-matched digitally.

[@Audio_Simon]

This is a fantastic video! On the HD test I could hear the distortion as fuzziness on the two higher levels. Really interesting is I could hear it as easily above 1KHz as below, even though the level went from 3% down to 1% at higher frequency. I think this is because our hearing is more sensitive in that range to HD and why these tests are critical for midrange and tweeters. Now this will be controversial... but I think HD plots are MORE useful than multi-tone!! 😲 Yes, when you listen to the tests the multi-tone tells you more, but the graphs are a different story. Firstly, we must understand that all 3 tests show the same thing - generation of 'phantom' tones. We simply hear / see more of them when we input more stimulus. When you look at the multi-tone graph it is not clear where the best high-pass point is for the driver. You had to run 3 'sweeps'. But with HD you can see where the non-linearity really picks up as the frequency goes lower. e.g. if you see the HD rise sharply below 100Hz then you KNOW the best multi-tone performance will come from a high-pass at 100Hz or above. Given that all 3 tests are showing the same non-linearity from the drivers motion, I wonder if a big brain could devise a transform to go from HD to multi-tone and backwards? Anybody??

[@Audio_Simon]

BTW I contribute by PayPal, but it sounds like you have some great discussion on Patreon so I'm gonna switch to that.

[@ErinsAudioCorner]

Thanks for the kind words and feedback!

[@Audio_Simon]

@@ErinsAudioCorner Hey Erin, I wonder if you could do a follow up test? Measure HD and multi-tone for 3 drivers and see how close the correlation between HD and multi-tone performance? I assume it is close, but I don't know how much. I think you'd need to high-pass all drivers at a point which is sensible for their use case or LF modulation would dominate everything.

[@raffima355]

Interesting thought, but i think there is one flaw. You are assuming that the effect of the nonlinearities is the same for sinewave and multi tone measurements. But it is not. A high HD in the bass region might be bad in some circumstances and in others not so. If the dominating nonlinearity is the suspension nonlinearity than there is basically no detrimental effect to the mid and high frequencies. The nonlinearity only has an effect around the resonant frequency of the driver (if I remember this correctly, its at least restricted to some frequencies). Even if we drive the chassis into high distortion in the bass frequencies it does not modulate higher frequencies. If we look at nonlinear inductivity you basically get the opposite effect. A bass note might heavily influence the inductivity of the driver which has a large amplitude modulating effect on mid and high frequencies. Both nonlinearities might produce 20% HD at 50Hz, but the effect on higher frequencies is hidden unless you use klippel equipment to seperate the nonlinearities or you use multi tone testing to see how much some nonlinearity bleeds into other frequencies. You can still use HD plots to determine the test signal of the multi tone test. If the distortion gets super high below 100Hz you should make a multitone test with maybe 50-2000Hz and then 100-2000Hz to see the difference

[@raffima355]

I would assume that in some cases a nonlinear suspension can even be beneficial. If we want to keep the driver from distorting in the mid and high frequencies we can use the nonlinear spider as a "limiter". A loud bass tone might still produce the same amount of distortion but at least the higher frequencies stay clean because it limits the driver from getting into issues with other nonlinearities (BL and Le). It think that's the reason for progressive spiders in pa speakers.

[@xprcloud]

Fully horn loaded speakers like the Klipschorn corner horn, and the klipsch la scala, minimize excursion, the principal by Paul Klipsch the higher the efficiency, the lower the distortion,

[@ErinsAudioCorner]

Indeed. And not just Klipsch. But, also remember that while distortion is audible, the main component is the frequency response. And that's something Klipsch has been known to ... alter... from time to time. 🙃

[@xprcloud]

@@ErinsAudioCorner No, I disagree , frequency response smoothness ( linear distortion ) is not as important as non-linear distortion, Linear distortion is correctable ( to a point ) for example with a DSP, non-linear distortion is always uncorrectable, as it is a form of data loss. I own fully active crossed over and time aligned corner klipschorns with a danleysoundlabs dts10, sub

[@ErinsAudioCorner]

@@xprcloud If there is smooth directivity then, yes, I agree with you. However, linear distortion isn’t always correctable. In fact; that’s the primary issue with many loudspeakers. They have poor directivity. Don’t think it just one axis. Think about all axes.

[@abdo-dr1tu]

From what little snippets you share about your personal life here and there i always thought you’re some sort of engineer. But now that you said You can’t math looks like i have to get my Nancy drew mojo going again 😂😂😂

[@ErinsAudioCorner]

Actually, I am an engineer. It’s a common joke that engineers are failed physicists because we don’t like math. At least among engineers. 😉

[@rustygates3367]

Engineers don't math, that what software and calculators are for! We just know what to math.

[@ErinsAudioCorner]

@@rustygates3367 exactly!

[@MK-um2rc]

You do hear Doppler distortion and amplitude modulation at the same time. Yes, AM is dominant but that doesn't mean you don't hear the other.

[@ErinsAudioCorner]

Just to make sure we are on the same page: I didn't say you don't. In fact, what I said in the video is that trying to make the distinction between the two is something I can't do unless you can somehow isolate the two like what Purifi has done on their website. 👍

[@MK-um2rc]

Yes, Erin. I totally agree with you that it's hard to tell between different types of distortions when they are mixed up, but psychoacoustic observation says you don't always need to clearly tell one thing from another to feel the subtle nuance of existence. Distinction requires a clear perception of two different things, but you can tell something more than one going on without being able to pin point each. You don't need to hear the exact number of hooves on a carriage wagon to tell there's more than one horse ;)

[@ErinsAudioCorner]

@@MK-um2rc haha. I understand what you’re saying. 👍

[@scottlowell493]

I don't know if you'd classify it as doppler distortion per se, but when ONE driver attempts to drive both low and high frequencies at higher volumes, it never sounds as good to me as separate drivers.

[@christiaanwillemsen1024]

Love the BL curve on the door 😋

[@ErinsAudioCorner]

LOL. Took me a second … had to go back and watch the video again but saw it right away. Good one!

[@Artcore103]

Seems like a good argument for 3 way and even 4 way design speakers... and even 3 way and 4 way speakers with a sub, so make that 4 or 5 way! Yeah you're dealing with a complex crossover network that can have it's own issues... but it seems like those issues are less significant than these distortions that can't be avoided since they're based on physics. This is why I like big speakers and my 15" woofers. For a given SPL their excursion is so much less, hence less distortion. Also why I like horns and waveguides... natural (physical) amplification via better impedance matching with the air, that results in higher efficiency, means for a given SPL your compression drivers are moving far less than a similarly sized mid/tweeter... lower maximum speeds and momentum of the moving masses. It just sounds quick and accurate and tight. Give me a 15" crossed between 500-1000hz, a 2" compression driver going up between 5k and 10k (generally nearer that 10k mark), and a super tweeter for the last HF octave or two, for a 3-way that's ideal to me. If you're going 4-way, you cut the 15" off even lower, maybe 150-200hz, then a 6"-10" that goes to 800hz-1.5k, then fill in with the 2" compression and super tweeter with the same upper ranges as before. Throw in a sub for everything below 40-50hz depending on the design and then you're really talking major SPL potential. When your woofers approach the physical size of a bass/kick drum, guess what they can cleanly emulate at realistic volumes? BTW the ideal horn ("waveguide") is the oblate spheroid... look at Geddes speakers... the horn/waveguide is round, with the OS curve, and is as large as the 15" woofer that accompanies it. Personally I'd add a super tweeter in theory... but the x-over is at or around 800hz. I don't own a pair unfortunately but my next DIY project will be an attempt to recreate it, with potentially even better driver selections, and a cabinet (and woofer) tuned to play lower, as his systems were meant to use a sub which I prefer to avoid in 2 channel listening (my current speakers easily play 30hz with authority and while 20hz would be nice esp. for movies, I don't miss it hardly at all with music). Best speaker design ever: www.gedlee.com/Loudspeakers/NS15.aspx

[@abdo-dr1tu]

By the way I don’t know if you noticed but the video kind of reminded me of how intrinsically distorted pianos are and how it’s a terrible material to listen to any sort of distortion.

[@roger_isaksson]

Just send white noise to the speaker and do a diff between the the input and output. Calculate the RMS of the error (distortion) signal.

[@ErinsAudioCorner]

If only it were that easy.

[@roger_isaksson]

Ever tried it? Any signal (BW limited) would do. Perhaps your favorite song? It’s classic ‘system identification’ techniques.

[@ukspawn666]

start doing multitone tests again !

[@ErinsAudioCorner]

I'm doing it!!!! haha. :)

[@ukspawn666]

@@ErinsAudioCorner I commented before you got to that part 🤷🤣👍

[@RennieAsh]

0:00 "doesn't matter" ;-)

[@Azzy_Mazzy]

good to know that my crossover at 100Hz is also better at lowering distortion

[@ErinsAudioCorner]

Indeed. Obviously the effect is different on different speakers. But this gives you an idea.

[@rhalfik]

Is it the same poor driver that Amir roasted in the last video? Also what are you talking about? I'm on this channel for the multitone testing. The most important info that you can provide about a midwoofer is how low and loud it can go without distorting the mids.

[@ErinsAudioCorner]

Nope. I didn't watch his video but if it's the speaker from GR Research then no, this is not it. What do you mean what am I talking about? :confused:

[@blakebrockhaus347]

It's not the same driver, but it's very similar

[@ErinsAudioCorner]

@@blakebrockhaus347 I've tested enough drivers from different build houses to know you can't assume they're the same or even similar. Even when the T/S look roughly the same, you can often get very different results. Especially when the motor/suspension linearity is different. One noticeably different aspect about the GR Research driver is the rolled surround where the PE driver has an inverted surround. For a midbass or even midrange driver this doesn't really matter. But for a full-range driver, this is a distinct difference. I haven't compared the GR driver to this one but with what I've said, I'd caution everyone to always reconsider thinking performance will be alike when two drivers look similar. Often the similarities stop at the size.

[@blakebrockhaus347]

@@ErinsAudioCorner oh absolutely. As far as tonality, off axis, detail, that can be vastly different. But as far as output goes, you're not going to be able to get much more out of a 3" chassis. Maybe a few db, but that's all

[@rhalfik]

@@ErinsAudioCorner Sorry, forgot the timestamp, now I'm confused as well :D There was a part where you said, that you stopped doing multitone because people were uninterested. I am interested. Everyone who designs speakers wants to know how big the enclosure can get, how low a driver can be used. Because two tones the way you do them here are just a linear travel expressed in a meaningful way. You can test the imd with different signals, but this particular pair is very useful.

[@Hexspa]

Haven’t finished watching this but I have some thoughts. Second-order harmonic distortion, subjectively, manifests as “cloudiness” or “thickness”. In isolated sine waves and above 3%, I wouldn’t say it’s totally masked (of course, that’s frequency-dependent with lower fundamentals effecting greater masking). That’s one thing. The other thing is very low frequencies like 20Hz. If your system reproduces it at all, it’s liable to distort at elevated levels and it can be extraordinarily noticeable. Now, is this the majority of use cases? No. But if you’re involved in audio production, it’s a phenomenon you’re likely to encounter at some point - particularly with modern electronic sounds; EDM or movies. FWIW, Genelec adheres to the GRADE standard which calls for, iirc, 1% or less from 250Hz up and 3% below of any single harmonic component at 90dB (not sure distance, let’s say 1m). I think harmonic distortion characteristics of transducers is important and sometimes noticeable. In any case, with Spinorama data, it’s another point to consider. Back to the video :)

[@Somesh-Ji]

Yeah, it's excellent...

[@ErinsAudioCorner]

Thank you man.

[@nicoras8803]

I am an audio Design engineer for some fifty years and if you are available for collaboration I would be keen to Expand on the issue GENERATING THEM AN TO CURB AND HOW TO CURB THEM

[@ErinsAudioCorner]

Sure. Shoot me an email sometime. hardisj @ Gmail dot com.

[@karlsonkab51]

(hope to listen to this later - my sound is "off"") There are some who might prefer a well done big horn rig driven by a classic single ended tube amp such as 2A3 output to a solid state amp with superb distortion figures and little speakers. I built a fair but not great parallel 2A3 amp driving by transformer coupled 5842Q and that drove Dr. Bruce Edgar's first horn speakers. CD which sounded nasty on other systems still sounded horrid but some analog LP "pretty good". A hobbyist might put together something like a Klipsch La Scala today for less than 1K per pair if they're able to do the woodwork. Peavey's FH1 was like the Belle and La Scala but better braced. These of course are not top end horn but reasonable. There;s apparently a standout midrange driver by PRV for around $70US which is as good or better than a K55V. "HOM" might be enjoyable in some instances (? I think it could add "reverb -?))

[@BastianUllr]

You diserve a F*ck*ng Nobel prize Erin!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[@neandrewthal]

The multitone distortion is mind-blowing to me. How come I have never heard of these measurements in headphones? I have been arguing for a headphones sound being completely decided by the frequency response as long as distortion is low enough and I have seen people argue that my prefered headphones are good with tones but fall apart as soon as you play complex music and that their headphones (which to me are snake oil, expensive and poor measuring ones) handle it well.

[@SlyNine]

I thought you said turn the volume up. RINGGGGGGGGGG

[@ErinsAudioCorner]

TURN DOWN FOR WHAT!?!

[@abdo-dr1tu]

Erin: I’m going to play 50Hz. The poor 3.5 inch full-range: 👁👄👁

[@kyron42]

80 bB is 80 dB regardless of your distance from anything.

[@ErinsAudioCorner]

Of course. But the speaker will have to work harder if that 80dB is at a further distance. People fail to understand this way too often. 80dB is 80dB if you're at 1 meter or if you measure it at 2 meters. But, if you start with 80dB at 1 meter and move to 2 meters, you drop 6dB and are now at 74dB. It’s relative.

[@JoshM7]

If It's doing 80dB at 1 meter but you walk away 3 meters and you're at 4 meters, you lost about 12dB from that 80dB. Which means 4 meters you only are hearing around 68dB which is what he meant by it's quieter. Because in the example 80dB is the assumed output at 1 meter, but you the listener might have walked away and now that 80dB is quieter because you aren't at 1 meter you're at 4 meters. Which means you hear 68dB+- even though it technically is playing 80dB at 1 meter. If you get what I mean.

[@idray986]

Yeah, my headphones are 80db on my head but on my desk 20 feet away they are just a few dB over ambient.

[@kyron42]

@@ErinsAudioCorner Of course you have to increase the gain of your amplifier to get the same loudness as you move away however saying that "80dB a few feet away is going to sound a lot louder than 80 dB 10 feet away" is incorrect. 80 dB is going to sound like a 80dB.

[@pliedtka]

Kyron, 80dB at 1m is our arbitrary reference level and in order for the same source to produce 80dB sound level at higher distance the acoustic power of the source has to be increased accordingly. I know you think of 80dB as level but for us it's the level of 80dB at given distance from the source. Yes, you feed more signal to it, but the cone works with much higher excursion thus producing much higher distortions.

[@chrisvinicombe9947]

I'm gonna pass on using headphones. Test tones are awful things to listen too. I'll try and get through this with my phone speaker (no promises).

[@ErinsAudioCorner]

100% understand.

[@chrisvinicombe9947]

I certainly heard the nasty with imd and multitone. Set off unpleasant resonances in my ears. Thanks for suffering through that stuff for us regularly.