16 Aug
2004
16 Aug
'04
4:25 a.m.
Lee Revell wrote:
On Fri, 2004-08-13 at 23:30, Erik Steffl wrote:
thanks for the info, now I have to figure out how to use it:-) it
looks like audacity uses oss (/dev/dsp) so I guess I could configure
alsa so that /dev/dsp is hw:x,0 and e.g. /dev/dsp1 is hw:x,2
right now I'm not even at the point of caring for latency, for some
reason the recording is of really bad quality when I use full-duplex
(i.e. playback of click track and record), the quality is OK if I only
record.
erik
recording seems to be working OK but:
in audacity when I record the track it sounds OK
however if I generate click track and record then (the click track is
playing while I am recording) the recording is really bad (noisy, low
quality).
I vaguely remember something about full-duplex on sounblaster not
being very good, i.e. there's something wrong when using it but don't
remember what (bitrate being forced to be very low or something along
those lines).
However I can't find any information on that subject now (I tried
google and creative site), does anybody know details and/or have some
pointers to relevant docs?
system: debian unstable, 2.6.5 kenrel (with alsa), sounblaster live
platinum (with live drive).
The hw:x,0 capture device on the sb live is not very good. For good
results you have to use the hw:x,0 playback device and the hw:x,2
capture device. You have to use 48khz.
To record at the lowest latencies you have to record more than 2
channels. This is because the capture buffer size is fixed in bytes;
doubling the number of channels halves the amount of time between
interrupts with a fixed buffer size.
This did not work at all until very recently, I believe you need the
ALSA 1.0.6-rc1 release candidate.
Search the recent alsa-devel archives for 'emu10k1 low latency capture'
and 'emu10k1 multichannel' for more info.