On Saturday 28 June 2008 17:49:35 Marc MERLIN wrote:
> I haven't found this anywhere in the FAQs.
>
> If I have a 5.1 sound card, i.e. a card that will drive 6 speakers, I would
> like to play 3 different stereo sounds on 3 pairs of 2 speakers so that I
> don't have to buy 3 sound cards.
>
> Is this doable? If so do you have a link to instructions and does this
> require a specific 5.1 card, or most should do?
I was fooling around with this a while ago. Heres what I came up with for
4,6 and 8 channel devices.
# Define 4 channel dmix with all the channels of your device
pcm.dmixs40 {
type dmix
ipc_key 1040
ipc_key_add_uid false # let multiple users share
ipc_perm 0660 # IPC permissions (octal, default 0600)
slave.pcm "hw:0"
slave.channels 4
slave.rate 48000
slave.periods 4
slave.period_size 4096
}
# now create the virtual stereo devices that mix into different stereo
# pairs within the multichannel device
pcm.s40_rear {
type route
slave.pcm "surround40"
slave.channels 4
ttable.0.2 1
ttable.1.3 1
}
pcm.dmixs40_front {
type route
slave.pcm "dmixs40"
slave.channels 4
ttable.0.0 1
ttable.1.1 1
}
pcm.dmixs40_rear {
type route
slave.pcm "dmixs40"
slave.channels 4
ttable.0.2 1
ttable.1.3 1
}
# six channels
pcm.dmixs51 {
type dmix
ipc_key 1051
ipc_key_add_uid false # let multiple users share
ipc_perm 0660 # IPC permissions (octal, default 0600)
slave.pcm "hw:0"
slave.channels 6
slave.rate 48000
slave.periods 4
slave.period_size 4096
}
pcm.dmixs51_front {
type route
slave.pcm "dmixs51"
slave.channels 6
ttable.0.0 1
ttable.1.1 1
}
pcm.dmixs51_rear {
type route
slave.pcm "dmixs51"
slave.channels 6
ttable.0.2 1
ttable.1.3 1
}
pcm.dmixs51_clfe {
type route
slave.pcm "dmixs51"
slave.channels 6
ttable.0.4 1
ttable.1.5 1
}
# and 8 channels
pcm.dmixs71 {
type dmix
ipc_key 1071
ipc_key_add_uid false # let multiple users share
ipc_perm 0660 # IPC permissions (octal, default 0600)
slave.pcm "hw:0"
slave.channels 8
slave.rate 48000
slave.periods 4
slave.period_size 4096
}
# Green jack : front
pcm.dmixs71_green {
type route
slave.pcm "dmixs71"
slave.channels 8
ttable.0.0 1
ttable.1.1 1
}
# Orange jack : centre+lfe (indep mode)
pcm.dmixs71_orange {
type route
slave.pcm "dmixs71"
slave.channels 8
ttable.0.2 1
ttable.1.3 1
}
# Black jack : (indep, dup-front off)
pcm.dmixs71_black {
type route
slave.pcm "dmixs71"
slave.channels 8
ttable.0.4 1
ttable.1.5 1
}
# Grey jack (doesn't work for me?)
pcm.dmixs71_grey {
type route
slave.pcm "dmixs71"
slave.channels 8
ttable.0.6 1
ttable.1.7 1
}
--
--
Eliot Blennerhassett
www.audioscience.com
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