[fluid-dev] Re: An evil screeching noise when playing

[Kimmo Sundqvist]

Toby wrote:

> Can you investigate further?

I installed 1.0.5 and played Overture to a New World by Chris Tilton.  The 
problem is repeatable, not dependent on the used soundfont (tried Unison and 
Merlin 22MB, and experienced it with both) or system load patterns.

The CPU usage, as shown by top, is 99% all the time, music or not, soundfont 
loaded or not, and I experienced no skipping.

I did not experience Fluidsynth going totally berserk, but it segfaulted once 
when I killed pmidi.

The screech comes at certain points in the song.  Imagine a wave hitting a 
rocky shore, but instead of water swooshing, imagine a sound much like a 
broken MP3 (with continuous CRC errors, with blips indistinguishable from 
each other, but no skips).  That is exactly how it sounds in the Overture.  
The envelope of the noise rises and decays exactly like a wave hitting a 
shore.

And it is not mathematical random noise, like one gets with

cat /dev/urandom > /dev/dsp

My ALSA is 1.0.9

Is it possible that there is a subformat of .sf2 or a format of compressed 
samples that Fluidsynth doesn't support?  This would be an odd coincidence, 
because changing the soundfont didn't change the noise in any way.

Playing a midi file with no soundfont loaded results in total silence.  Again 
Fluidsynth takes 99% of a CPU, but no noise (and no music) comes out.

-Kimmo S.