[ardour-users] cs46xx question

[Florian Schmidt]

On Fri, 20 Feb 2004 11:34:55 -0500
Dave Godin <dgodin at hologic.com> wrote:

> Hello
> 
> I am new to the list, as a result of my new Demudi install. I have
> very little experience with jack...I have to start jack with someting
> like this'jackd -d-alsa hw:0 -p64' When I open Ardour, I add a bus and
> then a track, select 'record' the sound meters spike AND it sounds
> like there is a humming or somekind of feedback going on. It is
> difficult to stablize the sound level, but when I do and try to
> record, it records for only a moment...there is lots of noise. Is this
> the result of my jackd settings or my sound card?

you probably feed ardours output back to the input somehow. This can
have several reasons:

1] feedback loop in the jack graph
2] feedback loop caused by selecting mix as capture source in alsamixer
3] feedback loop caused by feeding the soundcard output back into the
soundcard input [via hw mixer or whatever your soundcard is connected
to].

FYI [ignore the "[not implemented yet]"]:

tapas at mango:~/source/my_projects/tmp/pcm_config_test$ cat
/proc/asound/cards 
0 [CS46xx         ]: CS46xx - Sound Fusion CS46xx
                     Sound Fusion CS46xx at 0xcffef000/0xcfe00000, irq 5


tapas at mango:~/source/my_projects/tmp/pcm_config_test$ ./pcm_config_test
hw:0,0 -
-playback --capture --standard-periodcounts --standard-periodsizes

-- alsa-lib pcm device config tester v0.0.1 --

--CAPTURE:
---STANDARD_PERIODSIZES:
8
16
32
64
128
256
512
---STANDARD_PERIODCOUNTS [not implemented yet]:
1
2
4
8
16
32
64

--PLAYBACK: 
---STANDARD_PERIODSIZES:
8
16
32
64
128
256
512
1024
2048
---STANDARD_PERIODCOUNTS [not implemented yet]:
1
2
4
8
16
32
64

So, if you want to use jack in full duplex with this card the biggest
common periodsize is 512.

-- 
signature :)