EXS 24 Logic Sampler Users Group

Hendrik Jan Veenstra <h@...> wrote:


>
> Not sure if I understand you fully, but it sounds as if you're a bit 
> confused as to what samplers do.  What you describe is exactly what 
> _every_ sampler does: a recorded note is played back at original 
> pitch/tempo at a certain key (like C3), and if you stretch it across 
> the keyboard, higher notes will play a higher pitch by speeding up 
> the sample -- and thus shortening it.  Ditto in reverse for lower 
> notes.
> So a 1 second sample, assigned to "original key = C3" will last only 
> half a second when you play C4 and 2 seconds when playing C2.  That's 
> the basic principle of sampling and there's little you can do about 
> that.
>
> In order to avoid ugly artefacts you thus indeed need several sampled 
> pitches -- that's one of the reasons e.g. orchestral libraries 
> provide every single note instead of just one.
>
> What you're after is a kind of realtime "pitch change without 
> time-stretch".  There is software that achieves this, but note of 
> those is (afaik) realtime, since the algorithms involved are rather 
> complicated.  Logic's own built-in "Time & Pitch machine" is an 
> example of a piece of software that will let you do exactly this.



While I agree with nearly all of the above there are already some realtime
samplers/audio processors that do this.  Probably Celemony (I have only heard
the demos) and definitely Native Instruments Kontakt will do this for example. 

Kontakt doesn't do it very well though -- there are loads of obvious artifacts
as when operating in this way it uses a granular synthesis approach to achieve
pitch shifting without changing playback time. You wouldn't want to do this
with acoustic instrument samples unless you wanted to mangle them. 

I think we can expect this capability to become increasingly common now that
conventional software samplers are just about a dime a dozen and the processing
power is almost there now to do just about anything that DSP systems are
capable of -- eg physical modelling instruments etc -- just not all at once. 

Regards,
Murray