32kbps recording on windows doesnt record sound

[z-shan]

im able to record with 32kbps on firefox and chrome on MAC but doesnt work on windows. It shows it recorded but there is no sound. I dont get any errors in console. 64kbps works fine on windows.

[John-Page]

It appears that the sample rate of the input to Lame is set by the hardware. The Mac and PC use different rates. Chrome on Windows gets a rate of 48000 whereas Chrome on my Mac gets 44100. It seems that Lame cannot handle certain combinations of sample rate and requested mp3 bitrate.
I find that 32k bitrate fails on Windows (48000 sample rate) and 40k bitrate fails on the Mac (44100 sample rate). The failure mode is an mp3 file with the correct length but containing silence.
64k and 128k bitrate requests seem to work everywhere. I would like to use lower since my audio will be played over the cell connection and is only voice in mono.