laurent.artaud[AT]free.fr" <"laurent.artaud[AT]free.fr wrote:
> > One thing that I do notice is that if I turn my amp up to full while
> > connected to my 2496 soundcard I hear no hiss or noise at all.
> > Switch it to my SoundBlaster Live and wham! there is so much hiss,
> > even when all outputs are muted in windows ;-)
> >
>
> By the way, which 2496 sound card do you have?

Midiman Delta Dio

I have just done some tests on my system...

First off, the background noise level of my soundcard/amp/speakers is
about -93dB with the Midiman and about -65dB with the SBLive.  I have to
turn my volume control up to at least double what I normal use for music to
be able to hear the -80dB.  I suspect if burnt the WAV to a CD a played it
without my PC on and no other sounds I would be able to hear it at normal
listening volumes.

Next the square wave test.  I made a file split into two halves, all at
24/96.  The first half was just a pure 10kHz note, the second half was the
same but with a 30kHz note added with an amplitude of 1/3 (ie a square wave
filtered off at 48kHz).  Could I tell the difference?  Not a dicky bird,
even though the waveform looked quite different.

I even added harmonics at 20, 30 and 40kHz and could still tell no
difference from the pure 10kHz sine wave.

After a bit more testing, I found I could hear frequencies up to about
18.5kHz, so for me, a sampling rate of 41kHz would sound the same as
anything higher (assuming 10% bandwidth for non-perfect analogue filters).

This has all got rather OT :-)

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