On Monday 10 March 2008 06:22:21 Arnold Krille wrote:> Am Sonntag, 9. März 2008 schrieb Mark Knecht:> > On Sun, Mar 9, 2008 at 3:52 PM, drew Roberts <zotz@xxxxxxxxxxx> wrote:> > > On Sunday 09 March 2008 18:44:21 Mark Knecht wrote:> > > > Hi,> > > > I'm aware of and use standard Alsa methods to keep different> > > > sound cards in the same system straight as far as Alsa is concerned.> > > > I'm wondering what the proper process would be to keep 3 HDSP9652's> > > > which are physically in the same system, or multiple USB sound> > > > devices external to the system, straight as far as Alsa is> > > > concerned. I'd like to know that a certain card always will be> > > > always be card 0, card 1 or card 2. I do not want Alsa or Linux to> > > > make this decision for me and I certainly don't want Alsa to change> > > > them from boot cycle to boot cycle.> > >> > > I needed to solve this problem a while back. The best help I got was> > > telling me it was not possible.> >> > Humm, that's a pretty glaring disappointment, assuming it's true, and> > I have no reason to believe it isn't.>> Probably the one giving that answer was me. It is not entirely impossible.> The solution is roughly:> 1) You need to keep the clocks of the cards in sync. Not for the problem I had and I don't think for this problem either. I had 3 identical USB cards hooked to one machine. I wanted them seperate. I wanted them to come up in the same order each time. The problem was that they sometimes swapped order. This is not good when you are streaming multiple radio stations from the box. You end up with people tuning in to one stations stream and hearing a different station. I got solutions to fix the sound card order for cards which differed, but not for identical cards. Are there any solutions for identical cards? With NICs you can tie the order to the mac address. Is there something similar for sound cards?> - Either you got professional cards which allow to sync to adat/world> clock/spdif. Then its easy, just make them all sync to the same source.> - If you don't have that high cards:> Break out your soldering iron, unsolder the time-giving quartz on all> the soundcards except one and feed the quartz-signal from that "master" to> all the "slaves".> Now the cards don't fire interrupts at different times, because of> different sample-rates. (48kHz on one card is _always_ different then 48kHz> on another card if the clocks aren't synced.)> But they still fire individual interrupts...> 2) Break out you kernel-hacking skills and mask all the interrupt from the> soundcards except for one.> 3) Fiddle around with an .asoundrc to create one big sound-device out of> all these to-sync-devices.>> There are people who did this. (Search the web and the archives for> el-cheapo.)> But its not easy. And if you aren't fixed on "as cheap as possible" it is> easier and more reliable and more stable and of higher soundquality to just> buy a sounddevice that works and has the needed number of channels.>> That is why my answer is: It is not possible. Because it involves fiddling> with a lot of very advanced stuff and voids warranty on the devices if you> unsolder the quartz...>> Have fun, always try to. You too.>> Arnold all the best, drew_______________________________________________Linux-audio-user mailing listLinux-audio-user@xxxxxxxxxxxxxxxxxxxxxxxx://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
