[LAU] Jack chokes on merged device defined in .asoundrc

This is my first post to this list -- thanks in advance for advice. (Actually, I posted this first on the jackit mailing list as it seems to be a jack configuration issue, but it went ignored there for about 2.5 days so I'm trying again here.) I'm trying to configure Jack 1.9.6 on Ubuntu 10.04 (with real-time kernel) to use all four channels of an M-Audio fast track pro. The class-compliant USB audio driver reads a pair of stereo devices: card 1: Pro [FastTrack Pro], device 0: USB Audio [USB Audio] Subdevices: 0/1 Subdevice #0: subdevice #0 card 1: Pro [FastTrack Pro], device 1: USB Audio [USB Audio #1] Subdevices: 1/1 Subdevice #0: subdevice #0 I've set up a merged device in .asoundrc and tested directly against alsa, no problem: 1. Play a stereo, 44.1 kHz, 16 bit file to hw:1,0. 2. Play the same file to hw:1,1. 3. Use SuperCollider to make a four channel version of the same file, and play this to the merged device. All of these tests are successful -- so I think the .asoundrc configuration is correct. Jack can use either of the stereo devices -- hw:1,0 or hw:1,1 -- for playback with no problem. I've been using that successfully for almost two years now. But... (-Chw:1,1 is for the FTPro's stereo input) /usr/bin/jackd -S -P60 -dalsa -r44100 -p1024 -n2 -D -Chw:1,1 -Pft4 -s ... gives me: ~~~ JACK server starting in realtime mode with priority 60 audio_reservation_init Acquire audio card Audio1 creating alsa driver ... ft4|hw:1,1|1024|2|44100|0|0|nomon|swmeter|soft-mode|32bit Using ALSA driver USB-Audio running on card 1 - M-Audio FastTrack Pro at usb-0000:00:1d.0-1.5, full speed configuring for 44100Hz, period = 1024 frames (23.2 ms), buffer = 2 periods ALSA: final selected sample format for capture: 16bit little-endian ALSA: use 2 periods for capture ALSA: final selected sample format for playback: 16bit little-endian ALSA: use 2 periods for playback ALSA: could not start playback (Broken pipe) Cannot start driver JackServer::Start() failed with -1 Released audio card Audio1 audio_reservation_finish Failed to start server ~~~ Any ideas what I'm missing? Thanks, hjh -- James Harkins /// dewdrop world jamshark70(a)dewdrop-world.net http://www.dewdrop-world.net "Come said the Muse, Sing me a song no poet has yet chanted, Sing me the universal." -- Whitman blog: http://www.dewdrop-world.net/words audio clips: http://www.dewdrop-world.net/audio more audio: http://soundcloud.com/dewdrop_world/tracks