Dr. Herbert Melcher has shown that the brain has tipping points. Normally music is processed by the limbic centers; this is where toe tapping and other emotional reactions come from. When things go awry with the sound, the brain seamlessly transfers processing to the cerebral cortex- the seat of the conscious portion of the brain. When this happens, the emotion content of the music is diminished or lost.
The problem for digital is that it contains harmonics unrelated to the fundamental tones (instead are intermodulations related to the scan frequency). The ear is used to hearing harmonics that relate to the fundamental tones in some way. Now this inharmonic distortion (aliasing) is not a great amount, but the ear is very sensitive to any harmonic content that is higher ordered (uses it to measure sound pressure so it has to be sensitive) and is also tuned to birdsong frequencies (where many of the aliasing artifacts occur).
Hello Ralph, I missed that bit just prior to my last few posts.
that’s the part I’ve been looking for, with regard to having an argument that people accept. I’ve gone on about the harmonics, essentially inharmonic non-music related signal in class D amps and digital audio..for quite some time.
Engineering weighting says it is not important.
Human hearing says it is important. Fundamental. So fundamental that the inclusion of said inharmonic signal make the music and the gear...unlistenable for a notable number of listeners. That’s been my take on it since the beginnings of digital and looking at those waveforms on a scope or paper.
Then the folks who don’t find it to be objectionable, or not a problem.
The explanation seems to illustrate the issue of how and why different people listen. So the data to complete the question to most people’s satisfaction, regrading the potential correct answers, is in place. Thank you for that.
All my attempts at working with Class D amplifies, surround the idea of getting rid of that specific residual. I’ve had some success, but the purveyors of said modules, will not allow a modified module to be sold to the public, as that modded unit would be likely be perceived as better than all others of their manufacture, which may be installed in the given proffered finished product.
They said no, unless they could do the modifications for me at the manufacturing level, in house. Which means they wanted to sell my work to everyone (eventually sell to all others, or immediately tinker with the intellectual aspects) and retain their position in the drivers seat, in the finished amplifier manufacturing equation...as the provider of generic amplifier modules that everyone gets to eat (black box forced consumption of an unknown with different livery), and builders of amplifiers.... could just be a vehicle for their product. Like they are right now.
It’s a good business plan, if you can make it work, but a bit cold and hard, for my tastes. Manufacturers of class D modules have managed to get it to work so far, but my explorations in this area have certainly laid bare the business tactic, for me.
(KHotte of Teo Audio)
