latency info for computers producing audio

[SoundFNR@aol.com]

found this on the ComputerMuzys site

well explained, and figures too :-


< The "latency" thing : Why is there a delay between my MIDI input and 
audio 
output ?> 

Since all audio software must precalculate audio fragments before they can 
 
be send to the soundcard, and arrive to your ears, there goes some time 
between 
the moment some MIDI message is arrived at MIDI input, and the moment that 
the audio is ready, and is played through the speakers. 

Especially on the Windows(r) platform things can be quite serious. 

Windows itself, as an operating system, generates latencies (delays) of up 
to 
500ms (half a second !!!) between an incoming MIDI event, and reporting it 
to 
the application. And then the audio still has to be calculated and send to 
the soundcard. 

Though, starting from Windows 98, things are improving, and with a good 
setup 
and a good soundcard you may achieve latencies of 20ms or less. Especially 
if 
you use the ASIO drivers ! 

Even on faster systems like the Mac (latencies up  to 15ms), Linux (up to 
10ms) and BeOs (up to 10ms), the problem is there. And even on dedicated  
hardware machines like samplers and drumboxes, there are measurable delays 
! (Roland 
R8/R70 : 10ms, Yamaha O2R : 20ms, ...)