Re: [ecasound] capture from two delta 1010LTs at once

From: Bery Rinaldo <ecasound@email-addr-hidden>
Date: Thu Nov 17 2005 - 16:30:00 EET

>I was planning to use the word-clock output from card 1 to feed the
>word-clock input on card 2. The 1010LT does have S/PDIF in and out but
>I'm not sure if I need that.
>As for my initial question, I think I've figured it out...I should have
>been using "alsaplugin" instead of "alsa" when using the multi (all16)
>configuration I made. This command worked:
>ecasound -t:5 -a:1 -f:16,16,44100 -i:alsaplugin,all16 -a:1 -o:all16.wav
>Now on to learn more about "synchronizing sound cards" through personal
>experience ;-)
It turns out that the above command still does not capture the 16 analog
channels into a single wav file (the file is created but it is all
silence), so I've gone to this method which captures each channel in a
separate mono wav file:

ecasound -t:10 \
  -a:1,2,3,4,5,6,7,8 -f:16,8,44100 -i:alsa,analog8_1 \
  -a:A,B,C,D,E,F,G,H -f:16,8,44100 -i:alsa,analog8_2 \
  -a:1 -f:16,1,44100 -o:t11.wav \
  -a:2 -f:16,1,44100 -o:t12.wav -erc:2,1 \
  -a:3 -f:16,1,44100 -o:t13.wav -erc:3,1 \
  -a:4 -f:16,1,44100 -o:t14.wav -erc:4,1 \
  -a:5 -f:16,1,44100 -o:t15.wav -erc:5,1 \
  -a:6 -f:16,1,44100 -o:t16.wav -erc:6,1 \
  -a:7 -f:16,1,44100 -o:t17.wav -erc:7,1 \
  -a:8 -f:16,1,44100 -o:t18.wav -erc:8,1 \
  -a:A -f:16,1,44100 -o:t21.wav \
  -a:B -f:16,1,44100 -o:t22.wav -erc:2,1 \
  -a:C -f:16,1,44100 -o:t23.wav -erc:3,1 \
  -a:D -f:16,1,44100 -o:t24.wav -erc:4,1 \
  -a:E -f:16,1,44100 -o:t25.wav -erc:5,1 \
  -a:F -f:16,1,44100 -o:t26.wav -erc:6,1 \
  -a:G -f:16,1,44100 -o:t27.wav -erc:7,1 \
  -a:H -f:16,1,44100 -o:t28.wav -erc:8,1

As for the syncing of the two cards, it seems that S/PDIF is the way to
go for the Delta 1010LT. I used the envy24control GUI to select S/PDIF
In for the Master Clock for card 2 and set the "Locked" Rate State and
connected the S/PDIF output from card 1 to the S/PDIF input on card 2.
I ran the above capture command with the same analog signal (via a
Y-cable) going to one input on each card. I then compared the signals
in Audacity -- they were _very_ close -- I believe that the differences
may be due to ADC differences between channels. I tried the same thing
with two channels on the same card and there were similar differences.
I did also try using the Word Clock setting for the Master Clock and
connected the Word Clock output from card 1 to the Word Clock input on
card 2 using a male-to-male BNC cable, but ecasound gave overruns. If I
connected the S/PDIF along with the Word Clock, then no overruns, so it
seems that the Word Clock setting is somehow not working as I
expected...oh well, I'll stick with the S/PDIF method for now.

FYI, my application is to hook this rig up to the back of a soundboard
and capture up to 16 channels of a live performance for later
re-mixing/editing. If anyone else out there has a similar experience
with syncing two Delta 1010s, I'd be happy to hear from you.


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Received on Thu Nov 17 20:15:04 2005

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