Subject: Re: [linux-audio-dev] Correct sustain pedal emulation (midi hold controller) ?
From: Alfons Adriaensen (fons.adriaensen_AT_alcatel.be)
Date: Mon Oct 27 2003 - 19:38:39 EET
On Mon, Oct 27, 2003 at 05:00:55PM +0100, Benno Senoner wrote:
> Alfons Adriaensen wrote:
> >Most synths will just restart the note on the same voice in both cases,
> >i.e. begin a new attack phase at the level the previous (same) note had
> >reached during its release. So there will one be at most one note of a
> >particular pitch at the same time.
>
> Keep in mind that linuxsampler streams its samples from disk so we can
> use very large sample sets.
> There exist many high quality piano samples in .GIG format that have 4-8
> layers (velocity splits) for
> pedal up and pedal down samples.
> My question is mainly how to switch these samples.
> What do you mean with "i.e. begin a new attack phase at the level the
> previous (same) note had
> reached during its release" ?
> You mean velocity level ?
> Assume I press C2 with velocity 50 pedal up, the C2-pedalup (associated
> to velocity 50) sample sounds.
> Now I press the sustain pedal and press C2 with velocity 100.
> What should the sampler do ? Quickly fade out the C2-pedalup
> (velocity-50) note and trigger the
> C2-pedaldown (velocity 100) note ?
> And of course when you release the pedal all sustained notes will get a
> note-off.
I was thinking in terms of synthesizers using an envelope generator - not
playing samples.
I case a same note is played again while the pedal is on, I'd start
the new one and quickly fade out the old one at the same time.
But if the second one is softer than the first, the resonances of
the other strings will change too, if they are in the same sample
stream as the played note.
> One of the features that adds extra realism to Steinberg's /The Grand/
> ...
> Is that feature called "re-pedaling" ?
> IMHO it would be pretty easy to implement if you always start both
> samples (pedal-up and pedal-down) and then
> crossfade between the two when the user presses the pedal. (besides from
> the fact that you need to defer note-offs the pedal is down).
> Or does that sound bad ?
Fascinating problem :-) Cross-fading between two sample streams will be
audible if the phases of at least the fundamental and the strongest
harmonics are not the same in both streams. Maybe you will have to track
the phase of both streams in order to find the right places to x-fade...
Considering both cases, what you really need is a sample streams with only
the resonance sound for all notes at different velocities. These would then
pile up as long as the pedal is held...
-- FA
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