How to record sound from built in microphone

2024-11-14 19:25

Hello all,

I'm experimenting with the Luckfox Ultra W and experimenting with the audio. The speaker works fine, but I cannot get any sound from the microphone. I've been using arecord to do the recording as suggested in the wiki:

Code: Select all

arecord -f S16_LE -c 2 -r 16000 -D hw:0 -d 30 test.wav

There are many controls available in alsamixer and I've tried experimenting with adjusting them, but have not succeeded. How should I configure the soundcard to enable microphone recording?

Thanks.

2024-11-15 2:11

Hello, Luckfox Ultra uses a patch microphone with a small radio range. When receiving, you need to put the sound source close to the microphone. You can use ffmpeg -f alsa -i default -f alsa default command to record and playback the test. Compared with recording and then playing, the effect will be more intuitive.
If you are prompted that ffmpeg is not working, remove/oem/usr/lib/libfreetype* to ensure that you do not incorrectly link to Rockchip libraries.

2024-11-16 19:58

Thanks for the reply. I've tried moving right above the microphone and speaking loudly but still the recorded file is just silent. Could the issue be the settings in amixer/alsamixer? There are many options, it's not clear to me which ones necessarily relate to the microphone:

Code: Select all

[root@luckfox root]# amixer 
Simple mixer control 'I2STDM Digital Loopback Mode',0
  Capabilities: enum
  Items: 'Disabled' 'Mode1' 'Mode2' 'Mode2 Swap'
  Item0: 'Mode2'
Simple mixer control 'ADC ALC Left',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 31
  Mono: 6 [19%] [0.00dB]
Simple mixer control 'ADC ALC Right',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 31
  Mono: 10 [32%] [6.00dB]
Simple mixer control 'ADC Digital Left',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 255
  Mono: 245 [96%] [25.00dB]
Simple mixer control 'ADC Digital Right',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 255
  Mono: 244 [96%] [24.50dB]
Simple mixer control 'ADC HPF Cut-off',0
  Capabilities: enum
  Items: 'Off' 'On'
  Item0: 'Off'
Simple mixer control 'ADC MIC Left',0
  Capabilities: enum
  Items: 'Work' 'Mute'
  Item0: 'Work'
Simple mixer control 'ADC MIC Left Gain',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 3
  Mono: 2 [67%]
Simple mixer control 'ADC MIC Right',0
  Capabilities: enum
  Items: 'Work' 'Mute'
  Item0: 'Work'
Simple mixer control 'ADC MIC Right Gain',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 3
  Mono: 2 [67%]
Simple mixer control 'ADC MICBIAS Voltage',0
  Capabilities: enum
  Items: 'VREFx0_8' 'VREFx0_825' 'VREFx0_85' 'VREFx0_875' 'VREFx0_9' 'VREFx0_925' 'VREFx0_95' 'VREFx0_975'
  Item0: 'VREFx0_9'
Simple mixer control 'ADC Main MICBIAS',0
  Capabilities: enum
  Items: 'Off' 'On'
  Item0: 'On'
Simple mixer control 'ADC Mode',0
  Capabilities: enum
  Items: 'DiffadcL' 'SingadcL' 'DiffadcR' 'SingadcR' 'SingadcLR' 'DiffadcLR'
  Item0: 'DiffadcL'
Simple mixer control 'AGC Left Approximate Sample Rate',0
  Capabilities: enum
  Items: '96KHz' '48KHz' '44.1KHz' '32KHz' '24KHz' '16KHz' '12KHz' '8KHz'
  Item0: '96KHz'
Simple mixer control 'AGC Right Approximate Sample Rate',0
  Capabilities: enum
  Items: '96KHz' '48KHz' '44.1KHz' '32KHz' '24KHz' '16KHz' '12KHz' '8KHz'
  Item0: '96KHz'
Simple mixer control 'ALC AGC Left',0
  Capabilities: volume volume-joined enum
  Items: 'Off' 'On'
  Item0: 'On'
Simple mixer control 'ALC AGC Left Max',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 7
  Mono: 7 [100%] [28.50dB]
Simple mixer control 'ALC AGC Left Min',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 7
  Mono: 0 [0%] [-99999.99dB]
Simple mixer control 'ALC AGC Right',0
  Capabilities: volume volume-joined enum
  Items: 'Off' 'On'
  Item0: 'On'
Simple mixer control 'ALC AGC Right Max',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 7
  Mono: 7 [100%] [28.50dB]
Simple mixer control 'ALC AGC Right Min',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 7
  Mono: 0 [0%] [-99999.99dB]
Simple mixer control 'DAC HPMIX',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 2
  Mono: 1 [50%] [0.00dB]
Simple mixer control 'DAC LINEOUT',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 30
  Mono: 30 [100%] [6.00dB]

2024-11-18 1:32

Have you tried to use the echo test command first to determine whether it works properly?

Code: Select all

ffmpeg -f alsa -i default -f alsa default

tried to execute the record audio command you provided, using Audacity is able to see the waveform

Code: Select all

arecord -f S16_LE -c 2 -r 16000 -D hw:0 -d 30 test.wav

The system default mixer control settings can be recorded, you can refer to it

Code: Select all

[root@luckfox root]# amixer 
Simple mixer control 'I2STDM Digital Loopback Mode',0
  Capabilities: enum
  Items: 'Disabled' 'Mode1' 'Mode2' 'Mode2 Swap'
  Item0: 'Disabled'
Simple mixer control 'ADC ALC Left',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 31
  Mono: 6 [19%] [0.00dB]
Simple mixer control 'ADC ALC Right',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 31
  Mono: 6 [19%] [0.00dB]
Simple mixer control 'ADC Digital Left',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 255
  Mono: 195 [76%] [0.00dB]
Simple mixer control 'ADC Digital Right',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 255
  Mono: 195 [76%] [0.00dB]
Simple mixer control 'ADC HPF Cut-off',0
  Capabilities: enum
  Items: 'Off' 'On'
  Item0: 'Off'
Simple mixer control 'ADC MIC Left',0
  Capabilities: enum
  Items: 'Work' 'Mute'
  Item0: 'Work'
Simple mixer control 'ADC MIC Left Gain',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 3
  Mono: 2 [67%]
Simple mixer control 'ADC MIC Right',0
  Capabilities: enum
  Items: 'Work' 'Mute'
  Item0: 'Work'
Simple mixer control 'ADC MIC Right Gain',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 3
  Mono: 2 [67%]
Simple mixer control 'ADC MICBIAS Voltage',0
  Capabilities: enum
  Items: 'VREFx0_8' 'VREFx0_825' 'VREFx0_85' 'VREFx0_875' 'VREFx0_9' 'VREFx0_925' 'VREFx0_95' 'VREFx0_975'
  Item0: 'VREFx0_9'
Simple mixer control 'ADC Main MICBIAS',0
  Capabilities: enum
  Items: 'Off' 'On'
  Item0: 'On'
Simple mixer control 'ADC Mode',0
  Capabilities: enum
  Items: 'DiffadcL' 'SingadcL' 'DiffadcR' 'SingadcR' 'SingadcLR' 'DiffadcLR'
  Item0: 'DiffadcL'
Simple mixer control 'AGC Left Approximate Sample Rate',0
  Capabilities: enum
  Items: '96KHz' '48KHz' '44.1KHz' '32KHz' '24KHz' '16KHz' '12KHz' '8KHz'
  Item0: '96KHz'
Simple mixer control 'AGC Right Approximate Sample Rate',0
  Capabilities: enum
  Items: '96KHz' '48KHz' '44.1KHz' '32KHz' '24KHz' '16KHz' '12KHz' '8KHz'
  Item0: '96KHz'
Simple mixer control 'ALC AGC Left',0
  Capabilities: volume volume-joined enum
  Items: 'Off' 'On'
  Item0: 'Off'
Simple mixer control 'ALC AGC Left Max',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 7
  Mono: 7 [100%] [28.50dB]
Simple mixer control 'ALC AGC Left Min',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 7
  Mono: 0 [0%] [-99999.99dB]
Simple mixer control 'ALC AGC Right',0
  Capabilities: volume volume-joined enum
  Items: 'Off' 'On'
  Item0: 'Off'
Simple mixer control 'ALC AGC Right Max',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 7
  Mono: 7 [100%] [28.50dB]
Simple mixer control 'ALC AGC Right Min',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 7
  Mono: 0 [0%] [-99999.99dB]
Simple mixer control 'DAC Control Manually',0
  Capabilities: enum
  Items: 'None' 'Off' 'On'
  Item0: 'None'
Simple mixer control 'DAC HPMIX',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 2
  Mono: 1 [50%] [0.00dB]
Simple mixer control 'DAC LINEOUT',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 30
  Mono: 26 [87%] [0.00dB]