Strange behavior of 'sound' and 'sndplay'

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Emanuel Birge Emanuel Birge
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Strange behavior of 'sound' and 'sndplay'


I've been having a really strange problem with the sound-playback capabilities of scilab.

First, I'm loading a wav-file (Fs=44100,bits=16) ripped from a Bowers&Wilkins reference-CD into scilab 5.0.3 (so the quality should be top notch!)
When i play this wav-file with either 'sound' or 'sndplay' I hear this low-frequency chirping sound. I've managed to localize the chirping
to somewhere below 100Hz.

If I pass the audio through a highpass filter @100Hz, the chirping disappears. But the really really really strange thing is
that when I do a decimation to 22050kHz (only decimation, no anti-aliasing filter or other filters!) the chirping disappears also.
No matter how hard I think, I can't for the life of me figure out why this chirping appears in the first place (or
why it disappears when changing the sample rate).

This has led me to believe that there might be some sampling rate bug in scilab that is causing this chirp to appear,
but even that seems odd since someone should have noticed it already. Any ideas?

/Emanuel Birge, Sweden