[music-dsp] What is so special about 44100 Hz ?

Theo t.hogers at home.nl
Fri Jun 28 12:33:50 EDT 2002


No, play the file, reconstruction filter in your (or at least mine) sound
card can't handle it.
Even when the sample is taken from a 18kHz sine, most real live
reconstruction filters are not steep enough to do the trick.
Don't forget this is torture to demonstrate the limits of real systems vs.
theory,  not a musical context.

Theo



From: Matthew Craig <mcraig at optushome.com.au>

> Theo,
>
> > This is the most important point you cleared up for me.
> > In a mathematically idealized world the effects does not exist.
> > However on planet earth it can be demonstrated as the example wav file
> > showed.
>
> Remember that what you're seeing when you look at the WAV file is the
> sampled data, which must pass through the reconstruction filter before it
> reaches your speakers. So while on screen the waveform may look like it's
> amplitude modulated, as Greg pointed out, it won't be by the time it
reaches
> your speakers if you have a sufficiently steep cutoff in the recontruction
> filter. Even with a non-ideal filter, the amplitude of the modulation will
> be reduced somewhat.
>
> Try looking at your WAV file again in Cool Edit. IIRC the curves it draws
> between sample points emulate the response of a good (perhaps close to
> ideal?) reconstruction filter.
>
>
> Cheers,
>
> Matt.
>
>
>
> dupswapdrop -- the music-dsp mailing list and website: subscription info,
> FAQ, source code archive, list archive, book reviews, dsp links
> http://shoko.calarts.edu/musicdsp/
>


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