Re: [fluid-dev] SoundFont exclusiveClass

[Ceresa Jean-Jacques]

I Dan,

>Isn’t this the inverse of what the SoundFont spec says should happen? As the resonance value is increased, the DC gain should decrease, and the peak should not move:

 

Well, and in  this case we obtain a low pass filter, keeping the signal at cuttoff frequency (Fc) with constant level while other frequencies below this Fc have decreasing level. This filter is rather near of a selective filter. What you hear at the ouput are only the frequencies in the band pass of this filter. This is not the expected result in substractive synthesis practice. In many case certains frequencies need to be resonant (woods, and horns instrument) but not necessary to to the detriment of others frequencies. I'am pretty sure that Chris could confirm (or not).

 

This why the specs say:

"The resonance is measured as a dB ratio of the resonant peak to the DC gain. The DC gain at any resonance is half of the resonance value below the DC gain at zero resonance; hence the peak height is half the resonance value above DC gain at zero resonance."

 

It seem that we are out of the scope of initial question ?!

 

regards

 

jjc