I was planning to either run the cards on multiple USB Hubs or buy multiple PCI USB 2.0 cards and stick these in the back of the machine. I've bought 3 7-port USB2.0 hubs to hit my 16 card target.
The worst case scenario I had in my mind was that 4 PCI 4-port USB 2.0 cards would need to be fitted in the unit. It hadn't occurred to me that there would be a bandwidth limitation on, for example, 4 USB devices running into a USB 2.0 PCI card. Or a global bandwidth limit on the host controller. I've now been able to use aplay to send audio to 4 different sound cards all attached to the same USB Hub (though I haven't tried scripting this to happen simultaneously, so perhaps there's some kind of sequential allocation of bandwidth on the fly. Surely the headline bandwidth of USB 2.0 should be able to handle the bitrate of at least 4 audio cards, and preferably 16 or is the capacity not shared out this efficiently? Cefn http://curiositycollective.org On 11 Aug 2006, at 16:25, Lee Revell wrote: > On Fri, 2006-08-11 at 10:50 +0100, Cefn Hoile wrote: >> Now I have a way to address the cards, I need to implementing the >> virtualisation of these individual cards into a single mega-sound >> device! >> For anyone who's interested, the plan is to build this... >> http://cefn.com/curiosity/tag/pipedreams >> I'm using JJack to manipulate sound. Jack (the library addressed by >> JJack) can only address a single sound card, hence I'm diving into >> the alsa config to make 16 sound cards look like a single device with >> 32 outputs and 16 inputs. > > How many USB controllers do you have? There's no way you can run more > than one or two USB audio devices per controller - USB does not have > enough bandwidth. > > Lee ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
