Re: [ecasound] multiple input sound recording

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Subject: Re: [ecasound] multiple input sound recording
From: C.Lee Taylor (
Date: Sat Jun 07 2003 - 15:06:44 EEST

Hirendra Hindocha wrote:

    Greetings ...

>We've been using ecasound to record audio from one audio source
>and now we're looking for a solution where we can record audio
>from multiple sources and write it to the hard disk . I saw
>recently on the list about Delta 1010 card and its use in Linux
>based systems. Being a novice in this area, can anyone point me
>to a list of multi input cards that work with Linux ?
    Funny that somebody should ask this ask this today, I have been
working on a project that will require multi source recording. Our
current solution is to use multiple stero audio capture cards ( Off the
shelf sound cards ), then using ALSA, split the stero line into two
seperate channel inputs. Currently we have two sound cards for test,
but I beleive this shuld work for up to eight sounds cards, which should
give you sixteen mono channels. In my computer on my desk, I have one
on-board sound card, and five free PCI slots, which would mean I could
personelly test six device setup, which is 12 channels. Hoping to get
enough cards to test this. In all the docs I have read through, they all
warn about sync, xrun and latancy problems, but for what we will be
using it for, none of these are a problem.

>Is it possible for example to create a Linux based recording
>system that records from different audio inputs simultaneously ?
>If you have built one please share the info. If anyone can point
>me to other sources on the Net, so I can educate myself, please
>let me know.
    I test last night, the ablity to record from the four channels
indepentantly to ogg, with each recording taking about 10% of my CPU
while in X, using an Athlon XP 2000+ with 256MB DDR RAM, which I think
is fine. ( Side note, I was also about to use ecasignalview at the same
time, which I have not been able to do before.

    As for MultiChannel sound cards, that a look in the ALSA sound card
DB, and see what they have in there. I have seen a few people on this
list using a few differant ones. One of these cards, somebody in the
ALSA mail list used two of these 10Channel cards can worked a solution
to give them differant configurations that would be almost five 4channel
recorder. Again, through, there are alot of warnings about xruns (
which I don't really know what this means ), latancy problems ( which,
if I understand - means slow stop and start ) and sync problems, which I
think is got to do with all channels using the same clock source, but,
as I have said, this is not a problem with our project, but could be
with a pro mixer setup using Linux, but then it might be alot better to
use JACK.

    I hope this helps.


P.S. What an idot, I got so worked up, I did not give any details on how
I did it ...

Attched you will fine a copy of my around.conf, which splits the stero
channel input into to mono channel capture devices.

Following url describes the basics ...

Following url describes using Two cards as one, which with a little
google power, turn the other way around ...

You will need the following to setup Multiple cards in a system ...

Following url just plan tips for ALSA, which is good ...

Following url explains ALSA plugins, which I found too much for my
little grey matter ...

Following url gave me the basics to begin my little search ...

And this gave me an explaination that made sense ...

Have fun ...


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