Having sorted out my previous problem with Jack, I've got round to trying to sort out the multi-channel outputs via a MiniDSP UDAC-8. This is an 8-channel USB output device. I plugged it in and it shows up with 'aplay -': --------------------------------- **** List of PLAYBACK Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: ALC887-VD Analog [ALC887-VD Analog]   Subdevices: 1/1   Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 1: ALC887-VD Digital [ALC887-VD Digital]   Subdevices: 1/1   Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0]   Subdevices: 1/1   Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 7: HDMI 1 [HDMI 1]   Subdevices: 1/1   Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 8: HDMI 2 [HDMI 2]   Subdevices: 1/1   Subdevice #0: subdevice #0 card 1: UDAC8 [U-DAC8], device 0: USB Audio [USB Audio]   Subdevices: 1/1   Subdevice #0: subdevice #0 ------------------------------ Going into QjackCtl and changing the output device to hw:UDAC8 and it seems to work - jack restarts and the Graph window now shows system with 8 playback channels. I then tried using jack-play to play a short test .wav file which works fine on the ALC877 but fails with the UDAC-8: ------------------------------------------ Cannot read socket fd = 8 err = Success Cannot open jack-play-3712 client CheckRes error JackSocketClientChannel read fail JackShmReadWritePtr1::~JackShmReadWritePtr1 - Init not done for -1, skipping unlock JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock jack_client_open() failed: jack-play-3712 ------------------------------------------- I then tried using just alsa aplay -D plughw:UDAC8 which works, while aplay -D hw:UDAC8 fails with: ------------------------------ Playing WAVE 'test1.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo aplay: set_params:1349: Channels count non available ------------------------------ qjackctl only allows devices with hw:* and not plughw:* so that could be something, though I don't understand the internals of jack and alsa. Anyone able to set me right and get this to work will win my undying gratitude! Bill -- +----------------------------------------+ | Bill Purvis | | email: bill(a)billp.org | +----------------------------------------+