How to enable stereo recording on tablets/smartpho

Question

So far, I thought it was a firmware error, but now I just found a 2nd device that has two internal microphone capsules but only yields a monophonic signal (1st one was the S2 Plus GT-I9105P with Android 4.1.2 and now the HTC One M7; the Nexus 10 with Android 4.4.2 has only one mic).

I tested with:

bufSize = AudioRecord.getMinBufferSize(44100, AudioFormat.CHANNEL_IN_STEREO, AudioFormat.ENCODING_PCM_16BIT);
ar = new AudioRecord(source, 44100, AudioFormat.CHANNEL_IN_STEREO, AudioFormat.ENCODING_PCM_16BIT, bufSize);

and set source according to How avoid automatic gain control with AudioRecord?

I also tested some apps if they were able to produce real stereo recordings but did find none (I tested the standard Camera/Camcorder, Audiorecorder, and RecForge Lite).

So my question is: How to enable stereo recording on tablets/smartphones yielding only mono albeit having two internal microphones?

Add on question if there is no way to achieve real stereo recordings: Could you name other devices with also two internal microphones but only mono recording capability?

Is there any API or trick to find out programmatically?

Answer 1

See what worked for me in the Motorola Moto G. I understand it is very dependent on the vendor/model, but I tried many combinations until I found that only with 48000 Hz I was getting stereo recording in that particular phone:

Recording stereo audio with a Motorola Moto G (or Moto X)