How to record mono with arecord?

audio-recording, raspberry-pi, raspbian, speech-recognition

Solution

Your issue is weird, but I usually use sox for recording or conversion

You can use the rec command to record directly : `rec -r 16000 -c 1 -d 5 ~/test.wav`

In this case see also this question : https://raspberrypi.stackexchange.com/questions/4715/sox-alsa-sound-recording-issue

Or you can convert your wav file from stereo to mono : `sox ~/test.wav -c 1 ~/test_mono.wav` Documentation & examples : http://linux.die.net/man/1/sox

Problem

I'm using the SpeechRecognition package for text to speech. Its input for WAV files, however has to be mono. When I use `arecord -D plughw:0 --duration=5 -f cd -vv ~/test.wav` and I play it using `aplay test.wav` I get (it plays back): ``` Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo ``` How do I get `arecord` to record in mono? I have tried adding in `--channels=1` also but when it starts recording and displays information about its (`Plug PCM: Route conversion PCM`) setup, it always shows: ``` ... channels : 2 ... ``` My `USB PnP Sound Device`'s setup shows the channel is 1 though. Even though I've set it to 1, it plays back as stereo too. What's wrong?

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