Scott, I am not as optimistic re inaudibility of speaker distortion. I made tens and maybe hundreds of measurements of speaker nonlinear distortion and I cannot agree that distortion components are only low order harmonics. There are higher harmonics as well, measured at lower or moderate voltage like 2V. Much higher than in any normal amplifier. One of them as example.
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I still have several recorded wav files with speaker sine measurements. I am able to filter ambient noise and microphone path noise very well to get clean signals. At the moment I only have about 5 low distortion files. So it would need some additional measurements and some work. Like 1 day to prepare the test. Is it worth trying? Anyone would participate in the test? You can see how effective is the ambient noise extraction in attached images.
BTW, this one is inaudible, as expected.
Edit: found further one
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I am certainly not against measurements or 'proofs' about audibility or inaudibility, keep them coming! However, I find that just listening to a well set-up audio system tells us more than any measurements. I actually find that I can still hear subtle audio differences that don't actually measure effectively with total harmonic testing. Personally, once I got a test system that can reach significantly below -120dB, that what I measure is extremely boring, and next to useless. I leave that test equipment off for the most part. Actually I find that measurements below 0.01% that are mostly low order to be unhelpful in making better sounding audio designs.
Yet, I somewhat disagree with Dr. Geddes, in that he compromised his electronics at a relatively primitive level long ago, some sort of Japanese mid-fi amp. This does not work for me. IF his tests cannot tell any differences below that level of product, then there is something wrong with his test sensitivity to audio differences. And by the way, he and his wife are not the only people who have spent a professional 'lifetime' in audio research. Richard Marsh and I, for example have spent 50 years each, evaluating audio equipment sonic differences, as well, and there are many others who have as well.
IF I did not get regular feedback from serious audio listeners, I might just give up trying for better, but I do get both positive and negative input that helps refine present and future products, and I hope for more appropriate test methods like PIM distortion to be generally available in future.
Yet, I somewhat disagree with Dr. Geddes, in that he compromised his electronics at a relatively primitive level long ago, some sort of Japanese mid-fi amp. This does not work for me. IF his tests cannot tell any differences below that level of product, then there is something wrong with his test sensitivity to audio differences. And by the way, he and his wife are not the only people who have spent a professional 'lifetime' in audio research. Richard Marsh and I, for example have spent 50 years each, evaluating audio equipment sonic differences, as well, and there are many others who have as well.
IF I did not get regular feedback from serious audio listeners, I might just give up trying for better, but I do get both positive and negative input that helps refine present and future products, and I hope for more appropriate test methods like PIM distortion to be generally available in future.
Seriously? Now BeyerDynamic DT990s are "intermediate"? I thought you used Sennheisers, I consider them about the same quality. You seem to be grasping at straws to discredit someone else's work.
Asymmetric waveform (speech, kick drum etc) fed into a driver with asymmetric behavior will cause signal polarity dependent distortion of acoustic output.
Dan.
Just asking questions about the resolution of the test system. I have spent enough time in academia to know how things work there. Not always ideally, but not because people there are bad. There are often funding limitations for equipment, a need to graduate people and move on to the next thing. Sometimes there are legitimate academic disputes too. I want to keep making progress to get closer to the truth. Science is an ongoing process, and not every piece of work is the final word on everything. Take it easy, please.
You clearly didn't understand what I said. My issue was not with Richard's choice of purchase, but the dismissal of real research in a few words. M2s are possibly the most accurate speakers currently produced.
He stopped making them over a year ago. And good luck unless you are well connected in getting a home demo of M2s. JBL pro appear to have a low opinon of audiophiles. Not sure how Richard got his demo, but he clearly has the connections.
Chris: With 5 daughters I can always find a comb somewhere where I least expect it in the house 🙂
Hi Bill,
I only had three daughters, and finding a comb was never a problem either. It was more a concern with having to use one before first coffee!
-Chris
I only had three daughters, and finding a comb was never a problem either. It was more a concern with having to use one before first coffee!
-Chris
I look forward to your measurements and/or theoretical quantitative analysis.
OK, here is my first attempt based on older data collected about 2 years ago.
Test your ears in my new ABX test
I am starting new set of measurements and recordings that would be targeted especially to audibility of speaker non-linear distortion.
Ah. My nemesis is lurking...... Nothing I read of any paper from he or wife is significant -- except the HOM finding and his solution.
There are similar and many ways of controlling directivity. With horn, early attempts used an acoustic lens (see JBL). I used the LE175DLH - 90 degree lens in my experimental tri-amp'ed system in the late 1960's.
Wipe your nose.
THx-RNMarsh
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