sound – Using a tbone SC 420 USB mic on Ubuntu 20.04


I’m trying to use a tbone SC 420 USB mic on Ubuntu 20.04, but I can’t get it to record anything. The mic appears in sound settings, but never picks up any noise.

This is its entry in proc:

$ cat /proc/asound/cards 
 0 (PCH            ): HDA-Intel - HDA Intel PCH
                      HDA Intel PCH at 0x2ffb028000 irq 168
 1 (MICROPHONE     ): USB-Audio - USB MICROPHONE
                      USB MICROPHONE USB MICROPHONE at usb-0000:00:14.0-2.1, full speed

and I think the kernel modules are OK (and other microphones seem fine):

$ lsmod |grep snd
snd_hda_codec_hdmi     61440  1
snd_hda_codec_realtek   122880  1
snd_hda_codec_generic    81920  1 snd_hda_codec_realtek
snd_usb_audio         262144  3
snd_usbmidi_lib        36864  1 snd_usb_audio
snd_hda_intel          53248  3
snd_intel_dspcfg       24576  1 snd_hda_intel
snd_hda_codec         131072  4 snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec_realtek
snd_hda_core           90112  5 snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec,snd_hda_codec_realtek
snd_hwdep              20480  2 snd_usb_audio,snd_hda_codec
snd_pcm               106496  6 snd_hda_codec_hdmi,snd_hda_intel,snd_usb_audio,snd_hda_codec,snd_hda_core
ledtrig_audio          16384  3 snd_hda_codec_generic,snd_hda_codec_realtek,thinkpad_acpi
snd_seq_midi           20480  0
snd_seq_midi_event     16384  1 snd_seq_midi
snd_rawmidi            36864  2 snd_seq_midi,snd_usbmidi_lib
snd_seq                69632  2 snd_seq_midi,snd_seq_midi_event
snd_seq_device         16384  3 snd_seq,snd_seq_midi,snd_rawmidi
snd_timer              36864  2 snd_seq,snd_pcm
snd                    90112  25 snd_hda_codec_generic,snd_seq,snd_seq_device,snd_hda_codec_hdmi,snd_hwdep,snd_hda_intel,snd_usb_audio,snd_usbmidi_lib,snd_hda_codec,snd_hda_codec_realtek,snd_timer,thinkpad_acpi,snd_pcm,snd_rawmidi
mc                     53248  5 videodev,snd_usb_audio,videobuf2_v4l2,uvcvideo,videobuf2_common

but the device doesn’t seem to appear in lsusb:

$ lsusb 
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 002: ID 05e3:0616 Genesys Logic, Inc. hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 5986:2115 Acer, Inc Integrated Camera
Bus 001 Device 010: ID 24f0:0137  
Bus 001 Device 005: ID 3212:1a03  
Bus 001 Device 003: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 001 Device 002: ID 062a:0000 MosArt Semiconductor Corp. Optical mouse
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

There are some errors in dmesg which look suspicious:

$ dmesg | grep error | less
(    3.983808) EXT4-fs (nvme0n1p2): re-mounted. Opts: errors=remount-ro
(    4.597568) usb 1-2.3.2: device descriptor read/64, error -32
(  955.731572) usb 1-2.3: clear tt 1 (9092) error -71
(  955.731647) usb 1-2.3: clear tt 1 (9092) error -71
# Lots more error -71

but it’s not really clear to me whether these are related.

Any ideas?