Audio panel observation/question

I have a Garmin SL30 as my nav/com1 and a KY97A as my com2. My audio panel
is a King something-or-another with (among others) MIC1, MIC2 and BOTH
buttons. MIC1 and MIC2 are mutually exclusive and the BOTH switch works
independently.

When BOTH is off, MIC1 causes transmission and reception on only com1. MIC2
causes the same thing for com2.
If BOTH is also on, then you transmit on the selected radio but receive on
both.

I've recently noticed that BOTH causes the King com to have muffled and very
low audio output while the Garmin still has very strong audio. Whith BOTH
off and MIC2 selected, the King com has very strong audio.

I can live with this since the Garmin allows me to monitor the standby com
and nav frequencies while using the primary frequencies. I was wondering if
this is a sign of problems in the audio panel or possibly something else.
--
Best Regards,
Mike
http://photoshow.comcast.net/mikenoel