[iiwusynth-devel] More testing results

[Josh Green]

Well I did some more testing with iiwusynth looking for the filter
effect problem causing white noise. I'm sure you could probably figure
out this a lot easier than me :) It appears that all the problems I have
encountered with various instruments (Vintage dreams 0-6 - Dragon Sweep,
0-117 Warbling Bird 2 being killed viciously by static monster) are
related to the filter effect. I disabled the filter effect calculation
block in iiwu_voice_write (iiwu_voice.c) on line 432 (if (0)'d it) so
effect is always disabled. No more problems with white static noise.
Note that when white static is heard Floating Point Exception messages
are printed. Would be nice if the actual instruction causing exception
could be trapped, can it? My suspicion is that it is the FilterFC
parameter that is causing problems, from parameter tweaking that I
tested.

I also noticed on the filter effect that if the Q is set to 0.0 no
filter effect is heard. I think this is probably contrary to SF spec,
although I don't quite understand the explanation in the spec document.
I know it is contrary to how the SB AWE/Live! cards sound.

The other problem I found with max-polyphony related distortion appears
to be from CPU saturation. Looks like things need to be optimized
sometime :)

As far as ~ completion I decided not to do that, as its just easier to
specify the sound font from the command line for now.

Well, time for sleep. Lates..
        Josh Green