Re: [LAU] Audacity strange behavior

From: Folderol <folderol@email-addr-hidden>
Date: Tue Nov 11 2008 - 21:47:01 EET

On Tue, 11 Nov 2008 19:35:30 +0100
Fons Adriaensen <fons@email-addr-hidden> wrote:

> 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,

Thanks for going further into this. It's quite puzzling.

The thing is, where do we go from here? As I said in my previous post I
can confirm the ability to make identical copies directly, and via flac,
but I don't know how relevant the Audacity devs will think this issue
is.

-- 
Will J Godfrey
http://www.musically.me.uk
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Received on Wed Nov 12 00:15:03 2008

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