我正在用這個拔我的頭髮。我已經花了一天多的時間認真研究它，關注我能找到的每一篇文章。
歷史：
我建造了一台新機器用於鎖定（僅限 Ubuntu 20.04）。相當高端，但標準。
- 從後部線路輸出連接埠和通用 USB 網路攝影機運行的有源揚聲器（用於變焦會議，與攝影機內建麥克風相關）。到目前為止，一切順利，有點。
- 網路攝影機麥克風的品質很差，所以買了一個便宜的 USB 麥克風，品質也很差，但可以使用。
- 決定使用我現有的心形麥克風。因此購買了 Shure motiv mvi XLR 轉 USB 裝置。這就是問題開始的地方。無論我做什麼（由於 Shure 有一個耳機用於監聽目的），Ubuntu 都將其視為有效的接收器，並且由於是 USB，因此不斷將其設置為預設輸出。
我嘗試了很多方法，最終找到了將以下內容作為啟動應用程式運行的古怪解決方案：
pactl set-default-sink pactl set-default-sink
（看起來很奇怪，但是一個論壇推薦了它並且它起作用了。）幾個月後，在多次系統更新之後，我發現我不再需要「啟動應用程式」並停用它。
快進到昨天，以及我目前的問題。我決定購買外部 DAC（劍橋音訊 Dacmagic plus），settings > sounds現在我根本聽不到系統聲音、網路瀏覽器等。。
運行lsUSB，我可以看到設備。
運行aplay -L，列出設備：
surround21
2.1 Surround output to Front and Subwoofer speakers
surround40
4.0 Surround output to Front and Rear speakers
surround41
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50
5.0 Surround output to Front, Center and Rear speakers
surround51
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
null
Discard all samples (playback) or generate zero samples (capture)
samplerate
Rate Converter Plugin Using Samplerate Library
speexrate
Rate Converter Plugin Using Speex Resampler
jack
JACK Audio Connection Kit
oss
Open Sound System
pulse
PulseAudio Sound Server
upmix
Plugin for channel upmix (4,6,8)
vdownmix
Plugin for channel downmix (stereo) with a simple spacialization
default
Playback/recording through the PulseAudio sound server
sysdefault:CARD=C10
Cambridge Audio USB Audio 1.0, USB Audio
Default Audio Device
front:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
Front speakers
surround21:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
4.0 Surround output to Front and Rear speakers
surround41:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
Direct sample mixing device
dsnoop:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
Direct sample snooping device
hw:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
Direct hardware device without any conversions
plughw:CARD=C10,DEV=0
Cambridge Audio USB Audio 1.0, USB Audio
Hardware device with all software conversions
usbstream:CARD=C10
Cambridge Audio USB Audio 1.0
USB Stream Output
sysdefault:CARD=PCH
HDA Intel PCH, ALC1220 Analog
Default Audio Device
front:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Analog
Front speakers
surround21:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Analog
2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Analog
4.0 Surround output to Front and Rear speakers
surround41:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Analog
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Analog
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Analog
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Analog
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Digital
IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Analog
Direct sample mixing device
dmix:CARD=PCH,DEV=1
HDA Intel PCH, ALC1220 Digital
Direct sample mixing device
dsnoop:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Analog
Direct sample snooping device
dsnoop:CARD=PCH,DEV=1
HDA Intel PCH, ALC1220 Digital
Direct sample snooping device
hw:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Analog
Direct hardware device without any conversions
hw:CARD=PCH,DEV=1
HDA Intel PCH, ALC1220 Digital
Direct hardware device without any conversions
plughw:CARD=PCH,DEV=0
HDA Intel PCH, ALC1220 Analog
Hardware device with all software conversions
plughw:CARD=PCH,DEV=1
HDA Intel PCH, ALC1220 Digital
Hardware device with all software conversions
usbstream:CARD=PCH
HDA Intel PCH
USB Stream Output
hdmi:CARD=NVidia,DEV=0
HDA NVidia, HDMI 0
HDMI Audio Output
hdmi:CARD=NVidia,DEV=1
HDA NVidia, HDMI 1
HDMI Audio Output
hdmi:CARD=NVidia,DEV=2
HDA NVidia, HDMI 2
HDMI Audio Output
hdmi:CARD=NVidia,DEV=3
HDA NVidia, HDMI 3
HDMI Audio Output
dmix:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct sample mixing device
dmix:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct sample mixing device
dmix:CARD=NVidia,DEV=8
HDA NVidia, HDMI 2
Direct sample mixing device
dmix:CARD=NVidia,DEV=9
HDA NVidia, HDMI 3
Direct sample mixing device
dsnoop:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct sample snooping device
dsnoop:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct sample snooping device
dsnoop:CARD=NVidia,DEV=8
HDA NVidia, HDMI 2
Direct sample snooping device
dsnoop:CARD=NVidia,DEV=9
HDA NVidia, HDMI 3
Direct sample snooping device
hw:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct hardware device without any conversions
hw:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct hardware device without any conversions
hw:CARD=NVidia,DEV=8
HDA NVidia, HDMI 2
Direct hardware device without any conversions
hw:CARD=NVidia,DEV=9
HDA NVidia, HDMI 3
Direct hardware device without any conversions
plughw:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Hardware device with all software conversions
plughw:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Hardware device with all software conversions
plughw:CARD=NVidia,DEV=8
HDA NVidia, HDMI 2
Hardware device with all software conversions
plughw:CARD=NVidia,DEV=9
HDA NVidia, HDMI 3
Hardware device with all software conversions
usbstream:CARD=NVidia
HDA NVidia
USB Stream Output
sysdefault:CARD=MVi
Shure MVi, USB Audio
Default Audio Device
front:CARD=MVi,DEV=0
Shure MVi, USB Audio
Front speakers
surround21:CARD=MVi,DEV=0
Shure MVi, USB Audio
2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=MVi,DEV=0
Shure MVi, USB Audio
4.0 Surround output to Front and Rear speakers
surround41:CARD=MVi,DEV=0
Shure MVi, USB Audio
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=MVi,DEV=0
Shure MVi, USB Audio
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=MVi,DEV=0
Shure MVi, USB Audio
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=MVi,DEV=0
Shure MVi, USB Audio
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=MVi,DEV=0
Shure MVi, USB Audio
IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=MVi,DEV=0
Shure MVi, USB Audio
Direct sample mixing device
dsnoop:CARD=MVi,DEV=0
Shure MVi, USB Audio
Direct sample snooping device
hw:CARD=MVi,DEV=0
Shure MVi, USB Audio
Direct hardware device without any conversions
plughw:CARD=MVi,DEV=0
Shure MVi, USB Audio
Hardware device with all software conversions
usbstream:CARD=MVi
Shure MVi
USB Stream Output
usbstream:CARD=Camera
UVC Camera
USB Stream Output
- 運行
aplay -D plughw:C10 /usr/share/sounds/alsa/Front_Center.wav並播放（C10 是 dac 名稱） - 跑步時
speaker-test -c 2 -D plughw:C10，我依序從每個揚聲器中發出聲音。 - 即使運行變焦，如果我在設定中選擇 DAC，一切都會完美運行
- 但是運行
speaker-test -c 2 -D defaultorspeaker-test -c 2 -D pulse我得到：
speaker-test 1.2.2
Playback device is default
Stream parameters are 48000Hz, S16_LE, 2 channels
Using 16 octaves of pink noise
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 96 to 1048576
Period size range from 32 to 349526
Using max buffer size 1048576
Periods = 4
ALSA lib pcm_pulse.c:752:(pulse_prepare) PulseAudio: Unable to create stream: No such entity
Unable to set hw params for playback: Input/output error
Setting of hwparams failed: Input/output error
如果我運行aplay -D default /usr/share/sounds/alsa/Front_Center.wav我會得到：
ALSA lib pcm_pulse.c:752:(pulse_prepare) PulseAudio: Unable to create stream: No such entity
aplay: set_params:1407: Unable to install hw params:
ACCESS: RW_INTERLEAVED
FORMAT: S16_LE
SUBFORMAT: STD
SAMPLE_BITS: 16
FRAME_BITS: 16
CHANNELS: 1
RATE: 48000
PERIOD_TIME: 125000
PERIOD_SIZE: 6000
PERIOD_BYTES: 12000
PERIODS: 4
BUFFER_TIME: 500000
BUFFER_SIZE: 24000
BUFFER_BYTES: 48000
TICK_TIME: [0 0]
- 我嘗試了許多建議，例如重新安裝和重新初始化
pulseaudio以及alsa_base. - 我根據各種線程和帖子單獨對配置文件進行了大量調整。
- 我已經檢查
pavucontrol並使用過alsamixer。各種“修復”使事情變得更糟並被恢復，但問題仍然存在。 - 我已多次嘗試重新啟動脈衝守護程序，並且它啟動時沒有錯誤。
我知道這將是一件愚蠢而明顯的事情。 :)
非常感謝任何幫助。
答案1
我無法回答你的問題。然而，我之前以類似的方式問過一個問題，現在得到了答案。嘗試使用https://paste.ubuntu.com/或類似的服務，並提供終端輸出的連結。我認為這些帶有大量文字的問題往往會讓人們望而卻步。