Subject: Re: Gaussian vs uniform noise audibility From: Eckard Blumschein <Eckard.Blumschein(at)E-TECHNIK.UNI-MAGDEBURG.DE> Date: Thu, 22 Jan 2004 13:06:45 +0100At 04:46 22.01.2004 +0200, Israel Nelken wrote: >John Hershey's mail indicates the mathematical tools necessary to prove >my claims. These can be found I think in the Papoulis book, for example. Are you really sure that hearing can always be completely understood by means of linear treatment of an arbitrarily chosen section of time? Do you consider your retraction valid for any SPL, any variance, and any other parameter? Earlier you wrote: "... consider the fact that a Poisson sequence of clicks has a flat spectrum, like white gaussian noise, but sounds completely different." I see a lot of discrepancy between our tools and physiology: When we dealt with such clicks showing narrow peaks in excess of 140 dB SPL with a 100 kHz microphone while simultaneously 14 dB less with a slower one, we tried to improve the quality of recording by avoidance of clipping in the sound card. This successful effort made the difference between the original sound and the replay of its record tremendously worse. Dynamic range of hearing amounts at least 120 dB, apparently outperforming any linear audio equipment because perception of loudness is highly non-linear. Perhaps, Robert Masta should not be too cautious with respect to true amplitudes. I would rather ask for temporal and spectral limitations due to the arbitrary choice of the temporal window being as a rule rather different from physical and physiological restrictions. If I am suggesting FCT and restriction to the real, i.e. elapsed, time instead of FT and tacitly substituting the unknown future by mirrors of the past, this might be seen as merely an uncommon odd point of view, comparable to Feynman's notion of time running back and forth 'at a time'. Maybe, I failed convincing you of correctness and usefulness of natural spectrogram and joint autocorrelation. However, let's beware of blindly keeping a book like that of Papoulis a bible of hearing. Regards, Eckard