creative sb live! 声卡如何调整多声道？

[碧海蓝天]

Alsa 版本为1.0,16

ubuntu下 只能前面两个音箱出声 后置无声 如何调整？

02:05.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 07)
Subsystem: Creative Labs SBLive! 5.1 Model SB0100
Flags: bus master, medium devsel, latency 32, IRQ 20
I/O ports at b400
Capabilities: <access denied>

02:05.1 Input device controller: Creative Labs SB Live! Game Port (rev 07)
Subsystem: Creative Labs Gameport Joystick
Flags: bus master, medium devsel, latency 32
I/O ports at bc00
Capabilities: <access denied>

filename: /lib/modules/2.6.24-21-generic/ubuntu/sound/alsa-driver/pci/emu10k1/snd-emu10k1.ko
license: GPL
description: EMU10K1
author: Jaroslav Kysela <perex@perex.cz>
firmware: emu/emu1010_notebook.fw
firmware: emu/emu0404.fw
firmware: emu/micro_dock.fw
firmware: emu/emu1010b.fw
firmware: emu/audio_dock.fw
firmware: emu/hana.fw
srcversion: 5AC41DD1EAE51284B954C45
alias: pci:v00001102d00000008sv*sd*bc*sc*i*
alias: pci:v00001102d00000004sv*sd*bc*sc*i*
alias: pci:v00001102d00000002sv*sd*bc*sc*i*
depends: snd-pcm,snd-util-mem,snd-page-alloc,snd,snd-rawmidi,snd-timer,snd-hwdep,snd-ac97-codec,snd-seq-device
vermagic: 2.6.24-21-generic SMP mod_unload 586
parm: index:Index value for the EMU10K1 soundcard. (array of int)
parm: id:ID string for the EMU10K1 soundcard. (array of charp)
parm: enable:Enable the EMU10K1 soundcard. (array of bool)
parm: extin:Available external inputs for FX8010. Zero=default. (array of int)
parm: extout:Available external outputs for FX8010. Zero=default. (array of int)
parm: seq_ports:Allocated sequencer ports for internal synthesizer. (array of int)
parm: max_synth_voices:Maximum number of voices for WaveTable. (array of int)
parm: max_buffer_size:Maximum sample buffer size in MB. (array of int)
parm: enable_ir:Enable IR. (array of bool)
parm: subsystem:Force card subsystem model. (array of uint)