Re: [fluid-dev] [jOrgan-user] [FS reverb level sounds]

[David Henningsson]

On 2011-04-12 12:44, Graham Goode wrote:
> Hi David,
>
> ["base reverb level" in soundfont + CC91] level does not make
> mathematical sense to me.
>
> Base reverb level is given in % value, CC91 is 0-127. What is the conversion?

First, in the soundfont we have a reverb level at the instrument level, 
which ranges between 0 and 1, call this "I".
Second, in the soundfont we have a reverb level at the preset level, 
which ranges between -1 and 1, call this "P".
Third, if not overridden by the soundfont, there is a reverb modulator 
that tells that CC91 should affect the reverb level, which ranges 
between 0 and 0.2, call this "M". IIRC, it's linear, so M = CC91/127 * 0.2.
Fourth, the global FS reverb level, which we call "F".

Take the sum of I, P and M. Clamp it to be between 0 and 1 (i e, if 
greater than 1, it's 1, if less than 0, it's 0). Multiply with F.

Reverb level = F * clamp(I + P + M)

Hope that explains what you need to know as I might not have time to 
give more explanations today.

// David