Hi to all, I'm tryng to tune my machine to get the lower latency I can get with my hardware and linux of course. I have an audigy player with a debian sarge with the audio apps take from the unstable branch. I've recompiled the 2.4.22 kernel with capabilities, low latency, preempted patches. I've compiled the source packages of alsa 1.0.1 and jack 0.94. I can obtain a clean sound playing timidity thru my midi keyboard using 3 fragments each of 256 (but only if I'm root, otherwise I get "can't set sched_setscheduler" and the sound became dirty, maybe I have to recompile it?) which means a pretty low latency for me. On the other side I can run jack (jackstart works fine) with a period not less than 512, and I can't change the number of periods (neither increase) that is 2 by default. For example: $ jackstart -R -d alsa -d hw:0 -r 48000 -p 512 -n 1 [snip] hw:0|hw:0|512|1|48000|0|0|nomon|swmeter|rt|32bit control device hw:0 configuring for 48000Hz, period = 512 frames, buffer = 1 periods Couldn't open hw:0 for 32bit samples trying 24bit instead Couldn't open hw:0 for 24bit samples trying 16bit instead ALSA: cannot set number of periods to 1 for capture ALSA: cannot configure capture channel cannot load driver module alsa $ The same it is if I set number of periods higher than two (and that's strange, can be a configuration issue?) - Is it an hardware/driver limit, can't I reach the same latency that I have with timidity with jack? - Is it normal having 16 bit samples with my card? The last but not least, I have a general question about jack: if I a stream pass twice or more times into jack (for example alsa in -> jack rack -> ardour -> alsa out, 3 times) does the latency increases twice or more, proportionally, or it is only related to the various apps latency? Ok, I stop to bother anymore you with my (maybe stupid) doubts... Thanks for the attention, every answer will be greatly apprecciated. Ciao, Antonio
