From: Paul Wayper <paulway@ma...> - 2007-03-21 22:00:31
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I've been working away, composing on LMMS, and I think overall it's fantastic!
There's a few little niggles I have, like the way copy and paste is
inconsistent and hard to use, but the one problem that's bugging me at the
moment is that rapid successions of notes - even quarter notes - have a
'click' sound on the end. I've compiled a short demo that you can download at
http://mabula.net/music/note-click-demo.ogg that demonstrates the problem.
Looking at the waveform in Audacity shows that what's happening is that the
tone generation is simply being aborted and the waveform jumps rapidly, often
going too loud and being clipped but also sometimes wavering about and going
through nearly a thousand samples of random oscillation and noise. It also
seems to start notes by jumping from zero directly to the point in the cycle
that the oscillator currently happens to be going through.
All this is with the default TripleOscillator setting, which ordinarily has
its volume envelope turned off. But to me this is still a bug. All notes,
whether with or without a volume envelope, should start at the zero crossing
of their oscillator cycle, and be brought to zero in some suitable manner (my
preference would be to actually impose a 100msec release fade, but I'm open to
So I tried it with the envelope turned on, and got a similar problem
(available at http://mabula.net/music/note-click-demo-2.ogg). With this one,
the end of each note features a sudden burst to twice the amplitude, a fade
down and then return to normal amplitude, an immediate cut to zero and a brief
320 samples of noise, and then the next note starts by jumping to its
position. Interestingly, I note that the 320 sample break occurs in the
middle of the new note, and that the sudden burst is actually part of the new
note. I've also tried having two separate tracks playing alternate notes and
it still causes the same problem, even with a reasonable release time. So I
think this is a problem somewhere in the TripleOscillator.
If there's any way I can help further with this let me know, but unfortunately
I'm not a C++ programmer so I can't debug it directly. I'm running LMMS 0.2.1
from Subversion trunk head at revision 465, date 2007-03-07.
Hope this helps,
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