On Thu, 22 Feb 2007, Lee Revell wrote: > On 2/22/07, Eric <ef87@xxxxxxxxx> wrote: >> Hello, >> >> I am trying to figure out how to create an .asoundrc that will allow me to >> use Jack in the following manner: >> >> Use my Delta44 (ice1712) card as the primary capture/playback device. Use my >> on-board Intel 82801 (AudioPCI ?) as a secondary playback device, both of >> which I want to access through qjackctl at the same time. > > Not really possible - the cards will drift out of sync. Just to clarify, the crystal oscillators on the different cards to not run at the same rate. Thus say one runs at 44100 and the other at 44050. That means every second, the one card will bring in 50 fewer samples than the other one. If you remove enough samples to flush the second buffer, the first will have 50 left in it at the end of the first second, 100 the second, etc. If you try to remove enough samples to flush the first, the second buffer will not have enough samples in it to deliver to you. > >> >> I have tried many of the suggested methods using alsa "multi" but without >> any luck. >> >> I am having a difficult time understanding how to properly do this. >> >> jackd -d alsa -d playback > > Try "-P playback" rather than "-D playback". But even if you get jack > to run, it will not work well - you will get xruns due to the lack of > hardware sync between the cards. You have to either run both cards off the same crystal or select your cards really really well so that not only the crystal rates are identical but the variation with temperature, voltage, etc are identical as well. Now you can apparently buy cards such that the first holds, but I suspect since you talk about your onboard card as a backup, you also want to do this cheaply. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
