Originally Posted by
Boogie711
I suspect you're dealing with confirmation bias. The Shure's may indeed be losing volume. It may have happened to be during descent. I doubt they're related.
Maybe related to having been active for a couple hours? Maybe purely coincidental? But start looking into why your Shure's aren't so sure. I suspect you'll discover it has nothing to do with atmospheric pressure changes.
I do need to confirm on another flight, but it has happened consistently on the last several (4 or 5) flights which have been different lengths. I will do another test shortly and will check findings again...