Hi, I'm using a M-Audio Fast Track Ultra on Fedora 17. The device identifies itself as a 24 bit device. [romal at chessur card0]$ cat stream0 M-Audio Fast Track Ultra at usb-0000:00:1a.0-1.2.1.1, high speed : USB Audio Playback: Status: Stop Interface 1 Altset 1 Format: S24_3LE Channels: 8 Endpoint: 1 OUT (ADAPTIVE) Rates: 44100, 48000, 88200, 96000 Data packet interval: 125 us Capture: Status: Stop Interface 2 Altset 1 Format: S24_3LE Channels: 8 Endpoint: 1 IN (ASYNC) Rates: 44100, 48000, 88200, 96000 Data packet interval: 125 us Pulseaudio seems not to know S24_3LE for daemon.conf ? default-sample-format= The default sampling format. Specify one of u8, s16le, s16be, s24le, s24be, s24-32le, s24-32be, s32le, s32be float32le, float32be, ulaw, alaw. Depending on the endianess of the CPU the formats s16ne, s16re, s24ne, s24re, s24-32ne, s24-32re, s32ne, s32re, float32ne, float32re I tried several sample-formats, but none of them seem to work. cu romal