Could be any number of things!
Crude debugging methods:

1: ripple your 'out' opcode backwards, to audition intermediate results.
2: use the print opcodes to monitor levels.
3: look at your code ~really carefully~!
4: if all else fails, post your orc to the list. you never know - you may have
hit a bug!
Richard Dobson


David Schuyeteneer wrote:
> 
> My latest piece in Csound has annoying subtle distortion sometimes however
> the signal is **never** out of range !!
> I checked the range in a GUI sample editor and also Csound never said
> during
> the performance that there was even a single out of range sample.
> 
> anyone ?
>