[PlanetCCRMA] The el cheapo myth

Timo Sivula timo.sivula@luukku.com
Fri Sep 24 18:32:01 2004


in the past I was using Windows98 and N-track studio for most of my
audio recording work. I used two soundcards: an es1373 and an es1370
simultaneously and could record four independent tracks at once. Later
the 1373 card broke and I abandoned Windows for Fedora Core 1 and Planet
CCRMA. I now own 4 es1370 cards and for the sake of proving that it is
possible to do this in Linux I would like to achieve an 8 channel
multitrack recording capability with the cards in synch. Never mind the
availability of cheap high quality multichannel cards. This is more an
experiment to prove it is possible. The challenge falls into 2 separate
areas: a) the physical sync of the card clocks and b) to get the system
to work under Planet CCRMA. 

a) The physical sync problem can be solved by removing the chrystals of
all but one card, and connecting the "mclock out" of the previous card
to the "mclock in" of the next card, making the clocks chained behind
the master card clock. The cards have proper buffer circuits for the
clock inputs and outputs, so this connection should be a matter of
cabling and removing the excess chrystals. Having all cards behind one
chrystal should eliminate the possibilty of the cards falling out of
synch, in theory.

b) However, to test the system first one needs to get multiple
soundcards to work under linux simultaneously. I am not especially good
with the Linux configuration files, or software in general, and this has
proven difficult for me. This problem has been explained at planet ccrma
http://ccrma.stanford.edu/planetccrma/software/installkernelandsound.html#SECTION00023400000000000000 and http://alsa.opensrc.org/index.php?page=TwoCardsAsOne and I have tried to create the needed files according to these pieces of advice, to no avail. My problem starts with configuring the alsa modules to get all cards to work at once. I have not been able to get the cards to work after I modified modules.conf. With the alsaconf generated modules.conf only one card is available at once.  

Here is my modules.conf section on the cards which does not work. I get
no sound at all with this file. I am trying to get three cards to work
first, as I need one PCI slot for my wlan card: 

# --- ALSA configuration
alias char-major-116 snd
alias char-major-14 soundcore
alias snd-card-0 snd-ens1370
alias snd-card-1 snd-ens1370
alias snd-card-2 snd-ens1370
#alias snd-card-3 snd-ens1370
# 1st card
#-- OSS compatibility alias
alias sound-slot-0 snd-card-0
alias sound-service-0-0 snd-mixer-oss
alias sound-service-0-1 snd-seq-oss
alias sound-service-0-3 snd-pcm-oss
alias sound-service-0-8 snd-seq-oss
alias sound-service-0-12 snd-pcm-oss
# 2nd card
#-- OSS compatibility alias
alias sound-slot-1 snd-card-1
alias sound-service-1-0 snd-mixer-oss
alias sound-service-1-1 snd-seq-oss
alias sound-service-1-3 snd-pcm-oss
alias sound-service-1-8 snd-seq-oss
alias sound-service-1-12 snd-pcm-oss
# 3rd card
#-- OSS compatibility alias
alias sound-slot-2 snd-card-2
alias sound-service-2-0 snd-mixer-oss
alias sound-service-2-1 snd-seq-oss
alias sound-service-2-3 snd-pcm-oss
alias sound-service-2-8 snd-seq-oss
alias sound-service-2-12 snd-pcm-oss
## 4th card
##-- OSS compatibility alias
#alias sound-slot-3 snd-card-3
#alias sound-service-3-0 snd-mixer-oss
#alias sound-service-3-1 snd-seq-oss
#alias sound-service-3-3 snd-pcm-oss
#alias sound-service-3-8 snd-seq-oss
#alias sound-service-3-12 snd-pcm-oss
#-- Options
options snd major=116 cards_limit=3 device_mode=0666 device_gid=0
options snd-ens1370 index=0 
options snd-ens1370 index=1 
options snd-ens1370 index=2 
#options snd-ens1370 index=3 
# -- Keep modules from being autocleaned
add options -k snd-card-0
add options -k snd-card-1
add options -k snd-card-2
#add options -k snd-card-3
#--- ALSA configuration END

What could be wrong here? Any interest out there on the planet for this
kind of a project?

br, Timo