snd_hda: how to configure line-in passthrough to line-out?
brandon at 301south.net
Thu Oct 6 08:39:34 UTC 2011
On Wed, 5 Oct 2011, Polytropon wrote:
> On Tue, 4 Oct 2011 20:58:14 -0700 (PDT), Brandon Kuczenski wrote:
>> I'm working on the sound on my system running 8.2-RELEASE. Currently I
>> have sound input and output working using snd_hda (i.e. I can record on
>> line in, and play it back on line out).
>> What I would like to do is take the audio coming in on line-in and send it
>> back out the line-out "live" without recording it.
>> Is this easy to do? I'd appreciate any hints.
> I think it is easy to do. If I remember terminology
> correctly, the thing you're searching for is MONITOR.
> Instead of setting rec source to mic, set it to line,
> and increase monitor level.
Thanks for your assistance.. unfortunately, setting the mixer
levels has not been enough to get a passthrough. Here is my mixer output:
Mixer vol is currently set to 1:1
Mixer pcm is currently set to 45:45
Mixer line is currently set to 75:75
Mixer mic is currently set to 0:0
Mixer cd is currently set to 75:75
Mixer rec is currently set to 75:75
Mixer igain is currently set to 100:100
Mixer ogain is currently set to 50:50
Mixer monitor is currently set to 100:100
Recording source: line
I'm using wavplay(1) from the ports collection to record on line-in, and
then I can play it back. On playback I can hear it just fine-- it mixes
with other outputs on the PCM channel as I would expect. but when the
line is "live" it is not being mixed into the output.
> The line level should be possible to set independently
> of the rec channel setting, so you should be able to
> pass through line anyway - at least, that has been the
> default ability of sound cards when they became available
> for PC. But well... this has been 10... 20... years ago,
> and nobody expects simple things to work as simple today
> as they did in the past. :-)
Indeed, I wonder if it is a hardware capability problem, but I don't know
how to try to answer that question.
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