On Thu, May 8, 2014 at 12:59 AM, Enr G <e.glerean....@gmail.com> wrote: > My two cents as a person in the field: > > the human hearing system is kind of an LTI...
LTI is a very specific thing. It's not sort of, kind of, LTI--it's just either LTI or not. > only at very low level > processing. The consistency of measured signal (= perceiving the same > signal the same way at all time as somebody wrote here) is present in > the ear canal up to brainstem -> inferior colliculus. No, it's not. LTI means always stationary. Two easy ones that originate from the named region: 1. Stapedius response 2. Tinnitus I agree with the sentiment: There are multiple concurrent representations of sound, and at some level of auditory processing, sounds are frequently represented the same way. but it's not LTI--you have to ignore a lot of things to treat your auditory system as approximately LTI > But once we go > to higher neuronal processing of auditory signals things get > complicated and the same signal can be perceived in many different > ways (e.g. google for top-down mechanism of auditory attention). The > (non linear) fourier analysis and interpreting sounds as sinusoid are > valid at ear canal level, and there are models with filterbanks to > simulate that. But once we go to conscious perception (=cerebral > cortex) evidence from animal research seems to point to a more complex > analysis performed by the neurons: the so called spectro-temporal > modulation (basically a 2D fourier transform). I.e. envelopes and > phases are treated in different ways to identify "sound objects". For > those interested, this is a nice starting point (open access): > http://www.ploscompbiol.org/article/info%3Adoi%2F10.1371%2Fjournal.pcbi.1003412#pcbi-1003412-g007 Looks good--I read some very good articles from almost a decade ago (sigh) about the planum temporale (posterior temporal gyrus, right?). The Robert Zatorre articles on this topic were my favorite ones. > > e. > > On Thu, May 8, 2014 at 8:28 AM, 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 -- 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
