I get a deafening "chirp" from my 30G's when near/on the ground at airports with radar.
I get the same chirp from the Bose or the Passive DCs. The more powerful the transmitter, the worse the chirp. Usually I am the only one that hears it, even if the other person has a Bose.
A friend's Bose failed out of the box and instead of returning it to the retailer, Bose asked me to ship it to them directly. They also suggested an upgrade to my 1 y/o headset to get rid of a hot spot. The hot spot would only develop after about 7 hours of wear.
I overnighted both sets to Bose. They worked on and shipped the same day as they arrived. Shipping was overnight. Bose fixed the problem with the first set, gave both sets hi-tension springs (no more hot spot!), and replaced my ear cushions at no charge.
David Clark did the same thing when my 2 y/o headset mic failed. They replaced the mic, upgraded the cushion, and replaced the ear seals, then shipped the set back overnight.
I used the DC for two flights while my Bose was gone. It was like strapping on two brick amplifiers. The noise level was amazing (loud!), even with a set of ear plugs. My ears rang for hours afterwards.
A Lightspeed might be cheaper, but it certainly doesn't seem to withstand heavy use.
Fly SAFE!
Jedi Nein