Subject: Re: [ecasound] multi track recording problem.
From: Kai Vehmanen (k_AT_eca.cx)
Date: Tue Jan 29 2002 - 19:02:56 EET
On Mon, 28 Jan 2002, Bill Allen wrote:
> OK, I'm sure this is going to be embarassing, but I'm having a problem
> with multitrack recording using ecasound. Previous projects with ecasound
No need to worry about that. Better to ask than live in uncertainty. ;)
> ecasound -r -c -b:256 -s:multi.ecs
> -a:1 -i new.wav
> -a:2,3 -i alsa,default
> -a:2 -o new3.wav
> -a:1,3 -o alsa,default
> What I'm trying to do is monitor new.wav while recording a new track onto
> new3.wav. However, what I've found is that with no input, this setup
> copies new.wav onto new3.wav which isn't what I want at all. Is there
> something about alsa,default which works differently that /dev/dsp? Or am
> I just doing something really dumb?
Now that should definitely not happen. I tried with an identical setup,
and no audio was written to 'new3.wav' if nothing was played during
recording. What does the output of "aio-status" look like after you start
Anyway, there's another, usually better, way to monitor recording. First
you edit multi.ecs to contain:
-a:1 -i monitor.wav
-a:1 -o alsa,default
-a:2 -i alsa,default
-a:2 -o new.wav
... and then, from a mixer program (aumix, gmix, alsamixer or some other),
enable hw-monitoring. For instance with my ens1371 and ALSA-mixer, I
enable "Line input". Basicly most mixers allow you to set four setting
related to the inputs:
- what input is the recording source; (on consumer cards: mic or
- what is the input-level/gain (capture-level, input gain); in other
words the volume of signal going to the recording program
- whether the input signal is mixed to the master output; on/off (ie.
- line-in level; how much input signal is mixed to the master-output
Using hw-monitoring is better because you get much lower latency (you
hear it when you play it). Alternatively you could monitor even before
the signal gets to the soundcard (have a hardware mixer with
multiple outputs, one going to your monitor speakers, and one to the
All three variations work, and all have their pros and conds.
PS When loading from an .ecs file (with -s:xx.ecs), you should
put all chainsetup-specific options (= not global) to
the ecs-file, or otherwise they are not used. In your example,
"-b:256" is ignored, and the default buffersize setting of
"multi.ecs" replaces it. -c and -r on the other hand are global
options, so they should be outside the ecs-file (like they are
in your example). To further confuse you, in newer ecasound
2.1devX versions, even "-r" is a chainsetup specific. For a list
of all global options (there are only few of them), check
ecasound's man page and the "Global options" section.
-- http://www.eca.cx Audio software for Linux!
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