Hi, I recently bought a Creative Soundblaster USB sound adapter, for recording on my laptop (the inbuilt sound card doesn't bring the line inputs out to a connector, so it's useless for recording).
Alsa recognises the device, but alsamixer shows several channels that only half make sense to me. There are two pairs of RCA connectors labelled line in and line out; and a headphone jack with a volume control. Plugging anythinginto the headphone jack seems to mute the line output. Muting either `speaker' control from alsamixer also appears to mute the line output. Also it's as if the speaker volume controls are in series for line-in. But for PCM output, speaker 1 affects output levels, but not speaker 0. When a signal is going into `line in' it appears always to be echoed to `line out' regardless of any settings other than the speaker levels. Can anyone (perhaps who has used this device under Windows) explain the controls to me? Simple mixer control 'PCM',0 Capabilities: cvolume cswitch cswitch-joined Capture channels: Front Left - Front Right Limits: Capture 0 - 128 Front Left: Capture 24 [19%] [off] Front Right: Capture 24 [19%] [off] Simple mixer control 'PCM Capture Source',0 Capabilities: Mono: Simple mixer control 'PCM',1 Capabilities: cswitch cswitch-joined Capture channels: Mono Mono: Capture [off] Simple mixer control 'Mic',0 Capabilities: pvolume pvolume-joined cvolume pswitch pswitch-joined cswitch cswitch-joined Playback channels: Mono Capture channels: Mono Limits: Playback 0 - 255 Capture 0 - 128 Mono: Playback 0 [0%] [off] Capture 0 [0%] [on] Simple mixer control 'Auto Gain Control',0 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [off] Simple mixer control 'Speaker',0 Capabilities: pvolume pswitch pswitch-joined Playback channels: Front Left - Front Right Limits: Playback 0 - 255 Front Left: Playback 196 [77%] [on] Front Right: Playback 196 [77%] [on] Simple mixer control 'Speaker',1 Capabilities: pvolume pswitch pswitch-joined Playback channels: Front Left - Front Right Limits: Playback 0 - 255 Front Left: Playback 190 [75%] [on] Front Right: Playback 190 [75%] [on] -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html