I'm doing some testing for the future Musix 3 beta release, this time
on mobile devices and devices with less power than regular PCs.
I've notice that when you are not seeing the Rakarrack(RK) GUI (it's
minimized or in another desktop) -- btw, version 0.6.1 Equinox -- you
can hear a constant yet subtle crackling that you don't hear when
you're viewing the GUI.
In this case I was testing with a device with this specs rellating to
CPU and GPU:
* CPU type Intel Atom (Silverthorne)
* CPU speed 1200 Mhz
* Graphics Intel GMA 500
What I would like to know is if this is something you're aware or it's
just my case, and maybe the reasons why so I can get to a viable
solution if it's something wrong with my X configuration or Musix's.
Just to clarify, I work/play RT with no problem so at first the
crackling is not caused by jack miss-configuration or Xruns.
BTW, on this type of devices I usually use USB external audio
interfaces and work in Openbox, so all the resources are available for
applications rather than desktop environment or I/O processing.
I am not aware of this problem, and, it has not happened on any
computers I have tested:
Intel P4, 3.2GHz
Dual Core Intel 2.4GHz
iBook G4, 1.33 GHz
Toshiba laptop, 2.1 GHz
Operating systems include Debian Lenny, Debian Squeeze, and Sidux (now
Aptosid), and Linux Mint 11.
That I say maybe to help identify some possible differences.
If you can send a .wav file recording of some of this crackling to
ryjobil /at/ gmail \dot\ com then perhaps I can use it to identify a
In theory, the Rakarrack GUI should not be able to make noise on the
audio path like this, but I do have some ideas in my imagination if in
some way one of the FX parameters may be getting changed rapidly, or
randomly for some hard-to-understand reason.
All of the audio processing runs in its own thread, and the only
interface the GUI has is the ability to change parameters. If jack
does not report X-runs, then surely Rakarrack is generating this noise
in some way.
Here are some things you can also try:
Disable all the individual FX, and turn off the Rakarrack master enable
as well (jack going through, but Rakarrack having zero effect on the
signal). Then with all FX disabled, turn the Rakarrack master enable
on and see if this noise happens.
If in that condition there is no noise, then see if you can narrow it
down to a specific FX module or perhaps several...maybe is the same
problem on many different modules.
Another thing you can try is to launch it in headless mode (without
gui) and see if it still has noise. That can help us understand if the
GUI is doing something, or if it is something else.
Also, what inputs are being used? Could there be DC on a mic input?
Those are some things to start trying to find out why it does this.
Thank you for all your work on Musix. It is a great distribution :).