[ale] Sound question

[Ryan Marshall]

>
> I don't think so.  I used to build kernels all the time, but now
> I'd prefer to stick with distro-supplied ones if possible, for fear
> of breaking something else :-(
>
>
>>  Secondly, why aren't you
>> using jack?
>
>
> Mainly because of:
>
>
>  >> Now there are so many acronyms
>  >> and packages involved that I have absolutely no idea what they're
>  >> all doing.
>
>
> I do have jack installed.  When I tell csound to use it, via
> -+rtaudio=jack, it complains: "rtjack(): cannot connect to JACK
> server".  jackd is running.
>
>
>>  IIRC, I usually pull between 40 and 60 ms of latency and
>> that's a mostly vanilla setup.  I know it can get much lower with the
>> right tweaks and hardware.
>
>
> Just adding -+rtaudio=alsa to the csound command line reduced
> latency to negligible levels, although I'm getting a horrendous
> constant high-pitched whine and some nasty artifacts.  I can
> see I'm sort of on the right track, though.
>
>
>> Also, Jack may be a mess when it comes to the UI and config, but once
>> you figure it out, it really is a wonderful tool.
>
>
> The problem I'm having right now is being totally clueless about
> how all the layers of Linux sound architecture fit together, which
> ones I need and which not, etc.  I'd love to read something about
> how all that stuff is supposed to work together (ALSO, PulseAudio,
> JACK, etc).
>


Realtime kernel is not an issue.  Look in synaptic for the versions
with the -rt suffix.  They're generally a few revisions back, but
they've got the realtime stuff already baked in, so unless you're
running bleeding edge hardware, it's usually ok.

Linux sound architecture right now is a mess.  OSS, ALSA, Pulse and
Jack all address the shortcomings of the others while introducing
completely new problems of their own.  Mostly, Jack and Pulse sit on
top of ALSA and address routing the audio busses.  On my rig, when
Jack fires up, Pulse goes away.   I'm not sure where it goes, but only
Jack devices will produce sound when it's on.  I think Jack can write
straight to /dev/dsp, but I'm not 100% on that.  Once I got it working
well enough, I left it alone.  Jack can be a bit tempermental at times
and has a tendency to not play nicely when you swap audio hardware
around.

I understand that right now you're looking at doing something simple,
and admittedly I haven't played with Csound, but in the long run, I
think it's worth it to run on Jack.  If for nothing else, the advanced
routing functions make it worth it.  You could, for example, take your
Csound output, patch it through JackRack and have your PC act as a
multi-effects unit as well, or maybe just pull a little gain and
compression to compensate a bit for a impedence mismatch.  I know
you're almost where you want to be, but it's definitely worth looking
into.