I try to use a USB microphone such as this or this on raspbian (tested on Linux raspberrypi 4.1.18, 4.9.41 and 4.9.59). It is in the list of lsusb Bus 001 Device 005: ID 0d8c:013c C-Media Electronics, Inc. CM108 Audio Controller Bus 001 Device 004: ID 046d:c52b Logitech, Inc. Unifying Receiver 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. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

    and in the list of arecord —list-device **** List of CAPTURE Hardware Devices **** card 1: Device [USB PnP Sound Device], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0

    When capturing, I can only get a high background noise with a very low voice sound. I changed gain level from 100% to 70% with alsamixer and alsaclt without any change. In a noiseless environment, arecord —device=plughw:1,0 —duration=10 -vv atest.wav gives record at 61% (!?):

    1. Recording WAVE 'atest.wav' : Unsigned 8 bit, Rate 8000 Hz, Mono
    2. Plug PCM: Rate conversion PCM (48000, sformat=S16_LE)
    3. Converter: linear-interpolation
    4. Protocol version: 10002
    5. Its setup is:
    6.   stream       : CAPTURE
    7.   access       : RW_INTERLEAVED
    8.   format       : U8
    9.   subformat    : STD
    10.   channels     : 1
    11.   rate         : 8000
    12.   exact rate   : 8000 (8000/1)
    13.   msbits       : 8
    14.   buffer_size  : 4000
    15.   period_size  : 1000
    16.   period_time  : 125000
    17.   tstamp_mode  : NONE
    18.   period_step  : 1
    19.   avail_min    : 1000
    20.   period_event : 0
    21.   start_threshold  : 1
    22.   stop_threshold   : 4000
    23.   silence_threshold: 0
    24.   silence_size : 0
    25.   boundary     : 262144000
    26. Slave: Hardware PCM card 1 'USB PnP Sound Device' device 0 subdevice 0
    27. Its setup is:
    28.   stream       : CAPTURE
    29.   access       : MMAP_INTERLEAVED
    30.   format       : S16_LE
    31.   subformat    : STD
    32.   channels     : 1
    33.   rate         : 48000
    34.   exact rate   : 48000 (48000/1)
    35.   msbits       : 16
    36.   buffer_size  : 24006
    37.   period_size  : 6000
    38.   period_time  : 125000
    39.   tstamp_mode  : NONE
    40.   period_step  : 1
    41.   avail_min    : 6000
    42.   period_event : 0
    43.   start_threshold  : 6
    44.   stop_threshold   : 24006
    45.   silence_threshold: 0
    46.   silence_size : 0
    47.   boundary     : 1573257216
    48.   appl_ptr     : 0
    49.   hw_ptr       : 0
    50. ###############################+                   | 61%

    What is the tip to make it usable?