connecting a microphone via USB

[tad]

Dear Armin,

Thank you very much for your help.
I attached 'mytrace.txt' which was gathered as follows.

root@raspberrypi:/home/pi# strace arecord 1 2>mytrace.txt
root@raspberrypi:/home/pi# lsusb
Bus 001 Device 004: ID 0b0e:0420 GN Netcom Jabra SPEAK 510
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@raspberrypi:/home/pi# arecord -l
**** List of CAPTURE Hardware Devices ****
root@raspberrypi:/home/pi#

I have always activated privileged mode and mapped /dev/snd:/dev/snd on my netPI.
Even if Network=bridge to host, I see the same phenomenon between bridge and host.

I tried to reproduce 'mytrace.txt' again with a different USB device (microphone).
I will then inform you its result.

Best regards,