RME HDSP9632, mute headphones

RME HDSP9632, mute headphones

[Matthew Robbetts]

Hi all,

I've just acquired myself a HDSP9632 and noticed what I think is a
missing feature from the drivers (compared to Windows, at least): the
ability to set the headphones to "mute", in addition to -6dB and -12dB
of gain. I would find this feature useful.

Is there a reason it is missing or has it just been overlooked? Or,
alternatively, am I doing something stupid?

I'm using the alsa that comes with kernel 2.6.36-rc5 (I think it is
1.0.21?).

Thanks a lot,
Matt

Re: RME HDSP9632, mute headphones

[Florian Faber]

On 10/10/10 18:45, Matthew Robbetts wrote:

> I've just acquired myself a HDSP9632 and noticed what I think is a
> missing feature from the drivers (compared to Windows, at least): the
> ability to set the headphones to "mute", in addition to -6dB and -12dB
> of gain. I would find this feature useful.
> 
> Is there a reason it is missing or has it just been overlooked? Or,
> alternatively, am I doing something stupid?

This has nothing to do with the driver. You set the headphone volume
with hdspmixer, like you would do with TotalMix on Windows/Mac.


Flo
-- 
Machines can do the work, so people have time to think.
public key DA43FEF4          x-hkp://wwwkeys.eu.pgp.net

Re: RME HDSP9632, mute headphones

[Matthew Robbetts]

On 11 Oct 2010, at 06:32, Florian Faber <faber@faberman.de> wrote:

> On 10/10/10 18:45, Matthew Robbetts wrote:
> 
>> I've just acquired myself a HDSP9632 and noticed what I think is a
>> missing feature from the drivers (compared to Windows, at least): the
>> ability to set the headphones to "mute", in addition to -6dB and -12dB
>> of gain. I would find this feature useful.
>> 
>> Is there a reason it is missing or has it just been overlooked? Or,
>> alternatively, am I doing something stupid?
> 
> This has nothing to do with the driver. You set the headphone volume
> with hdspmixer, like you would do with TotalMix on Windows/Mac.
> 

Hi Flo,

Of course, you can adjust the volume digitally (though since hdspmixer overwrites all your routing every time you open it, it's a bit annoying to use). However, the card appears to have a dedicated a analogue gain stage just for the headphones. It's not a full PGA, but can be set to 0db, -6db, -12dB and mute - under windows. The ALSA driver only gives the first 3 options as controls. 

I had a quick look in the code, and it seems there's a 2-bit field in the 9632 control register for controlling this. Sounds neat, as we have 4 possible values. Can anyone confirm that the unused value (0x10, IIRC) in the ALSA driver is used to mute the headphones?

Regards,
Matt

Re: RME HDSP9632, mute headphones

[Matthew Robbetts]

hi Flo,

Thanks for your reply.


On 10/11/10 15:28, Florian Faber wrote:
> Matthew,
> 
>> Of course, you can adjust the volume digitally (though since hdspmixer overwrites all your routing every time you open it, it's a bit annoying to use). However, the card appears to have a dedicated a analogue gain stage just for the headphones. It's not a full PGA, but can be set to 0db, -6db, -12dB and mute - under windows. The ALSA driver only gives the first 3 options as controls. 
> 
> Ah, yes, that is something special with that old cards. I actually had
> to look it up in the manual.

Are you sure? I don't have one, but it looks like the AIO is very similar:
http://www.rme-audio.de/images/products/aio_set.gif

Anyhow - hardly important! :)


> 
>> I had a quick look in the code, and it seems there's a 2-bit field in the 9632 control register for controlling this. Sounds neat, as we have 4 possible values. Can anyone confirm that the unused value (0x10, IIRC) in the ALSA driver is used to mute the headphones?
> 
> I only have the sources for the newer cards, sorry. Just try it out,
> nothing bad should happen there.
> 

Hmmm, is there any advice you can give me on what might be affected or
need modifying to stay in sync? I've not contributed to a project like
this before...

The obvious ones to me are of course the driver itself, and adding a new
radio button to hdspconf. Is there anything else?

Thanks a lot,
Matt