Any ANR headset has to have a tight seal around your ear or the ANR
circuitry can't work right. The thicker your glasses frame the more
likely it will be that you'll have a problem.

Blanche wrote:

I just got a pair of 20-3G and the left side is "popping", doesn't
matter which aircraft. I spoke with Lightspeed on Tuesday and they
offered Step 1 to determine what the problem is -- the 20-3G have
the firmer ear seals. Since I wear glasses, they suggested using
the softer seals from my 15K. If that solves the problem, they'll
send me a new pair of softer seals for the 20-3G. If that doesn't
solve the problem, then call them for the RMA number to return
them.