Sound volume is too low

[Marc Plumet]

Problem description:
--------------------
Whatever system attached to my soundcard, the output level is too  low.
Same behaviour with different media player (cdcontrol/mplayer)
Same behaviour in Xwindow and in console

My system:
----------
Intel PIV - 1.7 GHz, 256 RAM
Motherboard : ASRock G PRO
 Audio : 5.1 Channels AC'97 Audio
FreeBSD 5.2.1 (February 2004)
Desktop : XFCE

Some (hopefully) usefull info:
------------------------------
Xcusco# dmesg | grep pcm
pcm0: <SiS 7012> port 0xd800-0xd87f,0xdc00-0xdcff irq 10 at device 2.7 
on pci0
pcm0: <C-Media Electronics CMI9739 AC97 Codec>

Xcusco# ls /dev/dsp*
/dev/dsp0.0     /dev/dsp0.1     /dev/dspW0.0    /dev/dspW0.1    /dev/dspr0.0

Xcusco# mixer
Mixer vol      is currently set to 100:100
Mixer pcm      is currently set to 100:100
Mixer speaker  is currently set to 100:100
Mixer line     is currently set to 100:100
Mixer mic      is currently set to 100:100
Mixer cd       is currently set to 100:100
Mixer rec      is currently set to 100:100
Mixer ogain    is currently set to 100:100
Mixer line1    is currently set to 100:100
Mixer phin     is currently set to 100:100
Mixer phout    is currently set to 100:100
Mixer video    is currently set to 100:100
Recording source: mic

Xcusco# kldstat -v | grep snd
                90 isa/snd_ad1816
                91 isa/snd_es1888
                92 sbc/snd_ess
                94 isa/snd_gusc
                95 isa/snd_mss
                96 acpi/snd_mss
                97 isa/snd_pnpmss
                98 gusc/snd_guspcm
                99 sbc/snd_sb16
                100 sbc/snd_sb8
                101 isa/snd_sbc
                102 pci/snd_als4000
                103 pci/snd_cmi
                104 pci/snd_cs4281
                105 pci/snd_csa
                106 csa/snd_csapcm
                107 pci/snd_ds1
                108 pci/snd_emu10k1
                110 pci/snd_es137x
                111 pci/snd_fm801
                112 pci/snd_ich
                113 pci/snd_maestro
                114 pci/snd_neomagic
                115 pci/snd_solo
                116 pci/snd_t4dwave
                117 pci/snd_via8233
                118 pci/snd_via82c686
                119 pci/snd_vibes
                120 snd_pcm
                160 msgsnd

[Question : which one should I use (cmi ? pcm ? pcm+cmi?)
and how to disable the other ?]

My questions:
--------------
I had a look on internet, in the handbook, in the mailing archive.
I found some more or less related topic, like :
- driver "forgets" to power on the ouptput amp.
- SiS7012 handles by /usr/src/sys/dev/sound/pci/ich.c

but nothing help till now.
Can someone tell me where to go now ?

Thanks a lot in advance.

marc