最近，我通过连接到 USB DAC（Audiolab Q-DAC）将我的音响系统从使用主板的内部音频输出升级到 USB2.0。第一次将 UBUNTU 12.10 连接到 USB DAC 成功了，但在系统升级（apt-get update & upgrade）之后。根本没有声音输出。我仍然可以在 Pulseaudio 控制面板中选择 USB 立体声输出选项，但没有声音输出。似乎连接已自动静音。我该如何取消静音？即使我升级到 13.04，也存在同样的问题。
我已将命令的输出转储lspci如下：
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v2/Ivy Bridge DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09)
00:14.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller (rev 04)
00:16.0 Communication controller: Intel Corporation 7 Series/C210 Series Chipset Family MEI Controller #1 (rev 04)
00:19.0 Ethernet controller: Intel Corporation 82579V Gigabit Network Connection (rev 04)
00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 1 (rev c4)
00:1c.4 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 5 (rev c4)
00:1c.5 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 6 (rev c4)
00:1c.7 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 8 (rev c4)
00:1d.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation Z77 Express Chipset LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 7 Series/C210 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation 7 Series/C210 Series Chipset Family SMBus Controller (rev 04)
03:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection
04:00.0 PCI bridge: PLX Technology, Inc. PEX 8606 6 Lane, 6 Port PCI Express Gen 2 (5.0 GT/s) Switch (rev ba)
05:01.0 PCI bridge: PLX Technology, Inc. PEX 8606 6 Lane, 6 Port PCI Express Gen 2 (5.0 GT/s) Switch (rev ba)
05:04.0 PCI bridge: PLX Technology, Inc. PEX 8606 6 Lane, 6 Port PCI Express Gen 2 (5.0 GT/s) Switch (rev ba)
05:05.0 PCI bridge: PLX Technology, Inc. PEX 8606 6 Lane, 6 Port PCI Express Gen 2 (5.0 GT/s) Switch (rev ba)
05:07.0 PCI bridge: PLX Technology, Inc. PEX 8606 6 Lane, 6 Port PCI Express Gen 2 (5.0 GT/s) Switch (rev ba)
05:09.0 PCI bridge: PLX Technology, Inc. PEX 8606 6 Lane, 6 Port PCI Express Gen 2 (5.0 GT/s) Switch (rev ba)
07:00.0 SATA controller: Marvell Technology Group Ltd. 88SE9172 SATA 6Gb/s Controller (rev 11)
0a:00.0 PCI bridge: Integrated Technology Express, Inc. Device 8892 (rev 30)
0b:02.0 FireWire (IEEE 1394): Texas Instruments TSB43AB22A IEEE-1394a-2000 Controller (PHY/Link) [iOHCI-Lynx]
0c:00.0 SATA controller: Marvell Technology Group Ltd. 88SE9172 SATA 6Gb/s Controller (rev 11)
尽管我在转储 lspci 之前已经连接了 USB 设备，但此输出转储似乎没有与 USB DAC 连接。为什么？
问候，戈登
答案1
系统升级后我遇到了同样的问题。对我来说，解决方案是将 DAC 的配置文件设置为模拟立体声输出。这可以在程序 PulseAudio 音量控制的配置选项卡中完成。