[LAU] Audacity strange behavior

[Fons Adriaensen]

On Mon, Nov 10, 2008 at 10:58:26PM +0000, Folderol wrote:

> OK, there are four files:
> 
> http://www.musically.me.uk/music/Test1.wav
> http://www.musically.me.uk/music/Test2.wav
> http://www.musically.me.uk/music/Test3.wav
> http://www.musically.me.uk/music/Test4.wav

I had a closer look. As posted before the difference is
noise, numerically generated (not analog) and strangely
lowpass filtered: -3dB at around 8 Khz going down to
-20dB at Fs/2. 

The noise power is -81dB FS, which is at least 14 dB
higher than would be required for any form of dithering
of 16-bit PCM. At least 2.5 bits are lost. No idea what
Audacity is trying to do, but it looks quite wrong.

Ciao,

-- 
FA

Laboratorio di Acustica ed Elettroacustica
Parma, Italia

Lascia la spina, cogli la rosa.