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Re: [fluid-dev] SoundFont parameter analysis
From: |
Tom M. |
Subject: |
Re: [fluid-dev] SoundFont parameter analysis |
Date: |
Thu, 21 Jun 2018 17:43:28 +0200 |
> The issue is the ModEnv attack and release times. The parameter is set in the
> PGEN (Preset) area, not the IGEN (Instrument) areas. It is set to 60ms attack
> and 50ms release, but the sound is more like 1.5sec attack and release,
> played back in Vienna Viena FluidSynth
The spec says: "Generators at the Preset Level are instead considered
“relative” and additive to all the default or instrument level generators
within the Preset Zone."
Both instruments set modEnvAttack and modEnvRelease to 100 ms. The preset
generator of e.g. Polysynth2 sets them to approx. 70 for attack and approx. 50
for release. This makes an attack of
100 ms * 70 = 7 sec
and release of
100 ms * 50 = 5 sec.
The modulation in this case affects the filters cut-off freqency. Thus it needs
7 seconds for the filter to fully open. This is pretty much what I hear. Dont
know about the 1.5 sec you refer to.
Note however that what you hear is strictly speaking not correct. fluidsynth
currently processes the modEnvAttack in a linear way. According to the spec
(8.1.2 #26) it should however be convex. See here for further reading:
https://github.com/FluidSynth/fluidsynth/issues/153
Tom