Derek Holzer wrote: > This could almost be the denormal problem again. Is it an Intel > processor on the MacBook? Intels are notorious for poor handling of > denormal numbers, which occur when the mantissa (decimal places) of a > number representing an audio signal becomes too long (such as happens > with reverb tails, etc). Check the archives for more than just a bit of > discussion on this, with some solutions (?) and certainly some workarounds.
Some solutions are presented here, with rationales as when each solution is best used: http://www.musicdsp.org/files/denormal.pdf In my exponential decay envelopes, I add a small number and subtract it again, which forces denormals (which are very close to zero) to be exactly zero. Example: if you have 4 significant digits: denoraml = 0.00000001234 denormal + 0.0001234 => 0.00012341234 truncate to 4 significant digits => 0.0001234 truncated - 0.0001234 => 0 (exact) This has to be done *within* the feedback loop, as that is where the denormals cause bigger problems. Other methods may be more appropriate for different scenarios... BTW: it isn't just Intel processors, on AMD athlon-xp I reduced CPU usage a fair bit too (although I hear Intel Pentium-4 is particularly bad). Claude -- http://claudiusmaximus.goto10.org _______________________________________________ [email protected] mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
