[PlanetCCRMA] Some basic FC3+Audio questions

Mark Knecht Mark Knecht <markknecht@gmail.com>
Tue Feb 8 11:26:01 2005

On Tue, 08 Feb 2005 14:01:21 -0500, Brian Panulla <brian@plutonian.com> wrote:
> Hi all... been lurking here for some time, but I've finally taken the
> plunge and set up a PlanetCCRMA system. I've been working with UNIX and
> Linux for about 13 years, but virtually all of that has been as a
> sysadmin via the command line or in plain old X. Using Linux as a
> desktop workstation with multimedia hardware is still a little foreign,
> so I'm thankful something like PlanetCCRMA exists!


> I'm generally having problems playing audio from the CCRMA apps. I'm
> thinking this is because of a lack of understanding on my part of how
> Alsa, JACK, and the non-Alsa apps/systems interact. Since these issues
> seem to cross application boundaries, I thought I'd ask here first... if
> there's something afoot that I need to research elsewhere, pointers
> would be appreciated.
> I'm running Fedora Core 3 on a Sony Vaio A250 notebook using the Intel
> chipset audio. My adapter is listed under the Gnome Soundcard Detection
> control panel app as "Intel Corp. 82801DB/DBL/DBM ... AC'97 Audio
> Controller using module snd-intel8x0. I DO hear the sample sound when I
> click "Play test sound" in Soundcard Detection.
> I've installed the "stable" low latency CCRMA kernel (2.6.10-2.1.ll) and
> tuned my hard disks as in the instructions. I've also run chkconfig to
> get alsa to start on boot.
> I've had a hard time getting audio CDs to play in XMMS. I did some
> digging and found that it was likely my CD drive did not support analog
> audio transfer, so I installed the cdread module for XMMS. I couldn't
> get any audio out of the CD until I played the test sound in my Gnome
> control panel. After that, CD audio plays fine. Does this make sense?
> Does playing the test sound load some module or start some service that
> is required for xmms?

Probably this is the issue. Try apt-get install alsaplayer and then
using alsaplayer play a CD. (Lower left CDDA item.) alsaplayer plays
CDs digitally. xmms will do it with some sort of plugin but I don't
use it.

> When I fire up qjackctl I am able to start JACK, though it complains
> about not being able to find the realtime capabilities of the kernel. 

Probably not important. This message is hanging around a bit.
'Realtime capabilities' has to do with the earlier kernels and the way
you got access to the hardware. I think it's changed in recent kernels
but the message hasn't. If you tell QJC not to use realtime (for now)
the message would go away.)

> I
> couldn't find any documentation on qjackctl... what does the "RT 0.24%"
> next to "Started" mean? is that an indication of latency performance?

RT = Realtime  -  0.24% is percent of CPU.
> Finally, I tried out Ardour. If I create a simple session, I can see the
> levels on the Ardour mixer react to my microphone, but when I record
> something, I can't seem to play it back. Am I missing a step here?

Possibly Ardour is not connected to your hardware output? Check in
QJC's connections page.

And again, welcome!

- Mark