[PlanetCCRMA] Problems with HDSPmixer settings

Mark Knecht Mark Knecht <markknecht@gmail.com>
Sat May 14 06:17:02 2005

On 5/14/05, Michele Spinolo <michele.spinolo@tin.it> wrote:
> Hi Guys (and Thomas :-),
> I am still trying to set up my convolver box, which is based on
> PlanetCCRMA@Home on FC3 and RME HDSP9652.
> Now the system is set up like this: RME HDSP9652 receives ADAT input from
> ADAT input 1, the CPU convolves the signal using AlmusVCU (Brutefir) and the
> output is given on ADAT output 1, which is connected to a RME ADI-8 Pro.
> The soundcard is setted in slave mode, reading the sync signal from
> wordclock input, which is provided by RME ADI-8 Pro.
> All inputs and outputs are setted to 0dB and...here comes the problem: in
> HDSPMixer 3 potentiometers lines are present: input, output and mixer (?).

No, the three lines represent

Hardware input
Hardware output

The mixer is not really visible. It's buried within the app and it's
pretty complicated so I'm not goingo to go over it right now as I
think it's not required for what you want to do.

To get sound from your convolver (assuming everything is on
alsa_pcm:output1/2) then you want to bring up the middle row to 0 and
the bottom row to a level that gives you the right overall volume.

> If the last one is set to -oo (- infinite) I hear no sound, while if this is
> set to 0dB I can hear some sound but it's crappy it is easy to hear that the
> mixer sound is overlapped by output sound (convolution introduce some delay,
> so it's easy to hear the overlapping sound).
> In HDSPmixer I can see I have sound on inputs and outputs (even if mixer is
> turned to -oodB) but I can hear no sound: I know "output sound" is the one I
> want because it turns off is the convolver is turned off.

This is the middle row. It's not the 'output' but it's the 'output
level of the app attached to alsa_pcm:output 1/2 routed to hardware
output 1/2'. I know. It's complicated. When you learn more about the
mixer you'll understand but it takes awhile.

> I triple checked all connection and everything seems fine, so I was
> wondering how to mute the mixer sound without muting the whole card.

Assuming that you do not have a mute enabled somewhere (at the channel
or the overall mute in the upper right) then bring up both the middle
row and the bottom row to get sound.

> Thank you very much!
> Michele

you're very welcome.

- Mark