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Re: Fw: EDP Oversampling



The Echoplex and the old sampler pitch change by really changing the 
sample 
rate on the D/A convertors. The newer sampler probably does it digitally 
by 
interpolation techniques or other DSP pitch-shift techniques, and 
maintains 
the same sample rate on the convertor. I don't think oversampling or the 
anti-alias filtering would have anything to do with the effect you are 
hearing.

Oversampling isn't "smoothing out" the waveform. It is a mathematical 
technique that spreads out the aliased frequency bands so they aren't 
right 
next to each other. That makes it simpler to filter out the aliased bands 
with a less-complex low-pass filter with a gentler slope.

kim

At 02:39 AM 6/24/2004, Jesse Ray Lucas wrote:
>I was just curious since comparing the sound of an older Akai S2000 
>sampler
>against the sound of a newer S5000 sampler.  Although both are 16-bit
>samplers, the older model sounds "grittier" when you pitch samples down or
>resample to a lower bandwidth.  The EDP sounds gritty, too, when you shift
>into halfspeed.
>
>As I understood that article it was saying that during the D-A conversion
>the oversampling process was the interpolation of in-between samples into
>the signal to smooth the waveform out.
>
>Just trying to figure out what makes that sound sound the way it does.  If
>you say it's the anti-aliasing filters that matter, then I believe you.
>Thanks for the info.
>
>-J
>

______________________________________________________________________
Kim Flint                     | Looper's Delight
kflint@loopers-delight.com    | http://www.loopers-delight.com