Apparently, at one point, audio playback through the speaker only used the left channel. See Internal speaker is left audio only - #3 by GuyPerfect for details. I think it'd be possible to use the left channel for music and the right channel for data if Panic added an option to disable the stereo to dual mono mixing.
You should be able to test this behavior by rebooting into recovery mode. As far as I can tell, the recovery firmware is version 1.11, whereas the mixing was added on 1.13.