>It would appear to me that the human hearing system is an LTI system. > It doesn't react in a linear fashion to frequency or loudness, but it perceives >the same signal the same way at all times, disregarding aging, hearing loss, etc.
One of the easiest ways to see that hearing must be nonlinear is to think about masking effects. In isolation, a signal will sound like one thing. But if you add another signal to it, then the sum will not sound like the sum of the two signals (generally). One of the signals may even disappear from your perception entirely! So, this can't be the product of a linear system. Also, you don't necessarily perceive the same signal the same way at all times (even ignoring aging, etc.). This is relevant to Sampo's loop experiment, actually. Take a loop of sound (any sound), say 1-2 seconds in length, and listen to it for a long time (say 1 minute or more). You'll find that after a while weird things happen to your perception of the sound, with some components seeming to move in and out of phase with others and so on. Which doesn't sound like a time-invariant system to me! E On Wed, May 7, 2014 at 10:28 PM, eric <ericzh...@gmail.com> wrote: > It would appear to me that the human hearing system is an LTI system. It > doesn't react in a linear fashion to frequency or loudness, but it > perceives the same signal the same way at all times, disregarding aging, > hearing loss, etc. > > On 5/8/2014 1:25:28 AM, Sampo Syreeni <de...@iki.fi>wrote: > On 2014-05-08, robert bristow-johnson wrote: > > > there was a way that you could do "subtractive dither" in that the > > dither that you added before quantizing to a short word could be > > subtracted (to regain 4.77 dB) [...] > > I have some code for just that, even, and even better ideas. Maybe I > even mentioned them somewhere a while back? If not, will fully share > given interest. (The code is rather shitty, and even the ideas would > benefit from development. But still better than you see implemented > anywhere.) > > Yet why-oh-why doesn't anybody just pop up their Audacity and a few > megabytes of randomness, the way I originally asked? Because the stuff > I'm talking about really is kind of interesting and unexpected, once you > try it out on your own ears... > > > when you loop the noise, is it a "butt-splice"? (i.e. no crossfade.) > > Yes. Otherwise the splice might introduce an interpolation artifact > which would invalidate the experiment from the start. > > > it's news to me that human hearing is LTI. > > Yes, well, it ain't. But even conventional psychophysical theory treats > it as such. For example, why would we hear frequencies unless the ear > was LTI? Fourier analysis, that is sinusoids as something special, > doesn't make much sense unless you assume... Well, you know, at least > something having to do with linearity and shift-variance... ;) > -- > Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front > +358-40-3255353, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 > -- > dupswapdrop -- the music-dsp mailing list and website: > subscription info, FAQ, source code archive, list archive, book reviews, > dsp links > http://music.columbia.edu/cmc/music-dsp > http://music.columbia.edu/mailman/listinfo/music-dsp > > > --- > This email is free from viruses and malware because avast! Antivirus > protection is active. > http://www.avast.com > -- > dupswapdrop -- the music-dsp mailing list and website: > subscription info, FAQ, source code archive, list archive, book reviews, > dsp links > http://music.columbia.edu/cmc/music-dsp > http://music.columbia.edu/mailman/listinfo/music-dsp > -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
