XM stereo input R/L reversed?

I’m running Ubuntu on the XM for a software defined radio application. The audio system is excellent for this purpose (although 96 kHz sampling would be even better :-). But I notice one oddity. The stereo input jack seems to have left and right reversed. I.e., the “tip” of the TRS connector comes out as the right channel, and the “ring” as the left. This is opposite the normal convention. The output jack seems to have the same problem.

I’ve fiddled with alsamixer settings, but I don’t find any way to change the R/L assignment.

Maybe this is a well known issue on the XM, but I’ve found nothing in the documentation or forums on the subject. (The schematics are even vague on this.) Am I missing something? It’s a trivial change in my software, except I like to be able to switch easily between built-in audio and USB sound cards.


Did you create ~/.asoundrc?
Have a look here:
and here

The L-R switch might be something like this:

## "Native Channels" stereo, swap left/right
    ttable.0.1 1
    ttable.1.0 1
## original normal left/right commented out
# ttable.0.0 1
# ttable.1.1 1


I have no clue if there is a design error in your BB!

This has came up before about 2 years ago. Right and left are not reversed in the hardware. I can’t speak for software.


It could be the Linux driver. Does anyone know?


There were some issues discussed for random switching audio channels
in lkml [1]. Don't know if this issue is matching here


[1] https://lkml.org/lkml/2013/3/29/126