I'm not really happy about the bit about JACK saying "as well as potentially multiple soundcards"... it seems unlikly to me that JACK will ever support that directly (without wordclock-like sync, when any system should be able to do it). Thanks for the timemachine plug though :) - Steve

Forgot to add that my assumption is (in addition to my previous statement) if JACK was then running using reasonably small buffers the drift would be then minimized if not alleviated since JACK is one that is dispatching the buffers at appropriate time, right? Ivica Ico Bukvic, composer & multimedia sculptor http://meowing.ccm.uc.edu/~ico/

On Fri, 2004-05-28 at 10:37, Ivica Ico Bukvic wrote: Having meddled some with this myself, and as Steve intimated, without the availability and ability of word-clock syncing between whatever cards being used in the multi card config, they drift at whatever settings you use from Jack and it results in distortion, xruns and all kinds of other nasties. I played with 2 identical SB Live 5.1's for some time in hopes of getting the "cheap fix" only to find that the oldest principle in life applies; You get what you pay for!" R~

On Fri, May 28, 2004 at 02:06:22PM -0400, Ivica Ico Bukvic wrote: yes, should work. -- Paul Winkler http://www.slinkp.com

On Fri, May 28, 2004 at 07:23:41 -0300, luis jure wrote: You think Free Software is cheap?! My time is quite valuable, and I recon I've put a good few man-months in. If I wanted a cheap solution I'd just buy a mac and a protools box :-| - Steve

On Sat, May 29, 2004 at 09:57:36 -0300, luis jure wrote: So was my reply. The combination of late nights, excessive coffee intake and british "humour" probably made it not obvious. - Steve

Steve, I wrote a whole email about this and decided not to send it. I feel strongly about this subject. Most people don't have time. But I think what it comes down to is *how* a person "pays". You can pay with *money* or you can pay with *time*. I love paying with "time". Because if I had (for instance) decided to go the windows or mac way, It would be much less hastle than the linux/audio/free-software approach. But when I toil (yes, I've "toiled" for hours and hours and days and months on some things) with a peice (or set of) software approaches, I've *learned* something. What does a person learn about the inner workings of audio on a modern computer system if you just install a peice of windows or mac software and spend your time (only) learning how to press record, stop, fast forward. I've paid with "time" and I'm very excited about how things are shaping up with my (home) linux audio studio. When I finally get things together, maybe I'll be able to give back to the community. But right now it's like a puzzle that will eventually come together and I will have exactly the progams that I really love all synced and doing what they need to do. BTW Steve, you (and many others here) have pointed me to some very good software/approaches/ideas. Thanks for all the help and work that you (and everyone else) has put in. Rocco

On Fri, May 28, 2004 at 02:01:17PM -0400, Paul Winkler wrote: yes. and surely this is a perfectly satisfactory solution for a small setup? Not sure 'hack' is really the right word. its not even a case of having expensive hardware. The $40 cmipci is capable of this. You can split the outputs (using appropriate impedance matching), and use one feed for audio and one for sync. So all you lose is the inputs on the slave cards leaving the inputs free for audio use on the master card. i vote that Ivo's comment "as well as potentially multiple soundcards" is (theretically) accurate. BUT, imo, any talk of using multiple unlocked cards is utterly futile in the context of Jack:-) cheers -- Tim Orford

"Ivica Ico Bukvic" <ico(a)fuse.net> writes: Many attempts have been reported. I don't recall any success stories, but maybe there were some. Most people want to do this with two cheap consumer "multimedia" cards. That won't work, because they can't be synchronized. -- joq

On Fri, 2004-05-28 at 10:55, Ivica Ico Bukvic wrote: The slower card will have to be fed something other than the source material from time to time to be able to catch up to the faster one (the "source" is coming at only one speed from only one place and going to two different places that need to be fed at slightly different rates). The "something to be fed" will be probably silence, that is, a click :-) The size of the buffer and the amount of drift between cards will determine how often you get a click (if the software would support doing this at all, of course). -- Fernando

Yes, of course that is doable. I don't think you need to profile them. Just measure the drift between the hardware pointers for both cards as you play. A long time ago (98/98 or so) I _have_ used two sb128 soundcards without sample sync to play back four channel pieces under linux. If the cards are of the same model and manufacturing batch the drift will be small. Small enough to play a 10 or 15 minute 4 channel piece without clicks[*] :-) Guilty :-) -- Fernando [*] but either the front or back speakers will slowly drift away from you as the piece progresses, not a real problem :-)