Re: [fluid-dev] Questions about soundfont, voice rendering, pitch shift...

[Pedro Lopez-Cabanillas]

On Thursday 03 February 2011, jimmy wrote:
> I'm trying to make a soundfont from a single audio sample (somewhere between 
> octave C3-C4).  The sample is about 4 seconds.  So it is set to the whole 
> range of notes (0-127).
> 
> What happens is the lower octave notes seems to lose some volume.
> 
> More problematic are the upper octave notes, they sounded so short (1-2 
> seconds, or less).  It may sound OK for short-duration sounds like like 
> piano, xylophone, but for synth strings, sawWave, squareWave, pads...  It 
> also sounds much less like the original sound.

For instruments with long sustain, like for instance flutes or strings, the 
usual practice is to define a loop in  the central part of the samples when 
defining the SoundFont. This loop will be played continuously by a synth until 
a note off event triggers the release part of the envelope. Some pointers that 
you may find useful:

http://en.wikipedia.org/wiki/Synthesizer#ADSR_envelope
http://www.creative.com/soundblaster/soundfont/tutorials/welcome.asp?articleid=54142&page=3

Regards,
Pedro