> >> Do surround51 works since you have a hardware volume knob but PCM playback volume is mono > > If I understood you correctly - I've took mono sound (wav from ALSA package) and played it through VLC, all channels work as expected. Card hw:2 'S51'/'Creative Technology Ltd SB Omni Surround 5.1 at usb-0000:00:14.0-6.2, full spee' Mixer name : 'USB Mixer' Components : 'USB041e:322c' Controls : 12 Simple ctrls : 5 Simple mixer control 'PCM',0 Capabilities: pvolume pvolume-joined pswitch pswitch-joined Playback channels: Mono Limits: Playback 0 - 128 Mono: Playback 91 [71%] [-18.50dB] [on] Seem no individual channel volume control Do this mean the balance slider in sound preference is useless ? Usually those multichannel usb audio devices have this type of volume control which is not supported by pulseaudio Simple mixer control 'Speaker',0 Capabilities: pvolume pswitch pswitch-joined penum Playback channels: Front Left - Front Right - Rear Left - Rear Right - Front Center - Woofer - Side Left - Side Right Limits: Playback 0 - 197 Mono: Front Left: Playback 196 [99%] [0.00dB] [on] Front Right: Playback 196 [99%] [0.00dB] [on] Rear Left: Playback 196 [99%] [0.00dB] [on] Rear Right: Playback 196 [99%] [0.00dB] [on] Front Center: Playback 196 [99%] [0.00dB] [on] Woofer: Playback 196 [99%] [0.00dB] [on] Side Left: Playback 196 [99%] [0.00dB] [on] Side Right: Playback 196 [99%] [0.00dB] [on] <a href="http://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/src/modules/alsa?id=527078523815587bfd021bc1d10782403e9b3e84">http://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/src/modules/alsa?id=527078523815587bfd021bc1d10782403e9b3e84</a>