После прописывания нужных модулей руками звук заработал: 
--- 
alias char-major-116 snd 
options snd major=116 cards_limit=1 
above snd-ali5451 snd-pcm-oss snd-mixer-oss 
alias snd-card-0 snd-ali5451 
alias char-major-14 soudcore 
alias sound-slot-0 snd-card-0 
alias sound-service-0-0 snd-mixer-oss 
alias sound-service-0-1 snd-seq-oss 
alias sound-service-0-3 snd-pcm-oss 
alias char-major-10-134 off 
--- 
unknown         : unknown (1002/cbb2/ffff/ffff) [BRIDGE_HOST] 
unknown         : ATI|PCI Bridge [IGP 340M] [BRIDGE_PCI] (vendor:1002 
device:7010) 
snd-ali5451     : Acer Laboratories Inc. [ALi]|M5451 PCI South Bridge Audio 
[MULTIMEDIA_AUDIO] (vendor:10b9 device:5451 subv:103c subd:0850) 
unknown         : Acer Laboratories Inc. [ALi]|M1533 PCI to ISA Bridge 
[Aladdin IV] [BRIDGE_ISA] (vendor:10b9 device:1533) 
slamrmo         : Acer Laboratories Inc. [ALi]|M5457 AC-Link Modem Interface 
Controller [COMMUNICATION_MODEM] (vendor:10b9 device:5457 subv:103c subd:0850) 
orinoco_pci     : Harris Semiconductor|Prism 2.5 Wavelan chipset 
[NETWORK_OTHER] (vendor:1260 device:3873 subv:1468 subd:0200) 
yenta_socket    : O2Micro Inc|OZ6912 CardBus Controller [BRIDGE_CARDBUS] 
(vendor:1217 device:6972 subv:1c01 subd:0000) 
usb-uhci        : VIA Technologies|VT82C586B USB [SERIAL_USB] (vendor:1106 
device:3038 subv:103c subd:0850) 
usb-uhci        : VIA Technologies|VT82C586B USB [SERIAL_USB] (vendor:1106 
device:3038 subv:103c subd:0850) 
ehci-hcd        : VIA Technologies Inc|VT8235 USB Enhanced Controller 
[SERIAL_USB] (vendor:1106 device:3104 subv:103c subd:0850) 
ohci1394        : Texas Instruments|TSB43AB21 IEEE-1394 Controller (PHY/Link) 
1394a-2000 [SERIAL_FIREWIRE] (vendor:104c device:8026 subv:103c subd:0850) 
unknown         : Acer Laboratories Inc. [ALi]|M5229 IDE [STORAGE_IDE] 
(vendor:10b9 device:5229 subv:103c subd:0850) 
unknown         : Acer Laboratories Inc. [ALi]|M7101 PMU [BRIDGE_OTHER] 
(vendor:10b9 device:7101 subv:103c subd:0850) 
natsemi         : National Semi|DP83810 10/100 Ethernet [NETWORK_ETHERNET] 
(vendor:100b device:0020 subv:103c subd:0850) 
Card:ATI Radeon : ATI Technologies Inc|Radeon IGP 340M [DISPLAY_VGA] 
(vendor:1002 device:4337 subv:103c subd:0850) 
unknown         : Virtual|Hub [] (vendor:0000 device:0000) 
unknown         : Virtual|Hub [] (vendor:0000 device:0000) 
unknown         : unknown (062a/0001/ffff/ffff) [Human Interface Devices|Boot 
Interface Subclass|Mouse] 
unknown         : Virtual|Hub [] (vendor:0000 device:0000)