On 03/12/12 08:47, Carlos sanchiavedraz wrote:
Hi again, dear Rakarrackers.

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.

Thanks in advance.

Carlos sanchiavedraz
* Musix GNU+Linux
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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 root cause.

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 :).

Take care,