[LAU] asoundrc questions

[Len Ovens]

On Mon, December 31, 2012 8:33 am, John Murphy wrote:
> On Mon, 31 Dec 2012 11:10:31 -0500, Paul Davis wrote:
>
>> On Mon, Dec 31, 2012 at 11:07 AM, John Murphy
>> <rosegardener at freeode.co.uk>wrote:
>>
>> > I'm trying to follow the example .asoundrc provided at
>> > http://alsa.opensrc.org/RME_Hammerfall_.asoundrc
>> >
>>
>> what are you trying to accomplish?
>
> Hello Paul. Thanks for asking.
>
> I'm hoping this is the way to use jack on both cards at the same time.
> I'd also like to configure most inputs as stereo pairs. I'm hoping
> mixers will then provide a single fader and pan control.

The .asoundrc will make it possible for jack to see the two cards, though
if you read the thread on the two deltas, you will understand it is not
perfect :) It works better for some people than others.

As for mixers... which mixers? Any of the applications that provide mixers
like ardour or non-mixer (anything that deals with jack ports) allow you
to choose which inputs belong to a channel. So you can create a stereo
channel with input 1+2 or 1+7 if that is what you want and use a pan
control (or something more advanced). As for the alsa mixer, changes to
the .asoundrc look like they may effect that. For most uses the alsa mixer
is pretty much set and forget though, so I am not sure how valuable that
is. In any case, jack does not show stereo pairs anyway. In any case any
stereo pair should be confined to one card. It should not be left from
hw:0 and right from hw:1 as the stereo imaging will suffer. It is ok to
mix sound from a stereo pair on one card with the sound from a stereo pair
on another card though... so long as the sounds are not acoustically
related (recorded from mics sets that are recording the same sounds).

I don't know how the rme cards work if they use phase lock loop to sync as
the cheaper deltas do. In any case it is best to use the channels from the
master card (the one supplying clock) for the most important audio. Cable
length should be kept as short as practical for sync.

Best of all, try it and see.

-- 
Len Ovens
www.OvenWerks.net