Amazing hearing protection - Bose 30 earphones

[physics-teacher_imp]

Do any of you guys with qc20s know if they can be used with an old fashioned audio device like a boom box or a cd player? These have what used to be called a standard stereo headphone jack, only three contact points on the plug while the qc20 seems to have four. I see adapters for the awkward airplane set up, but do not see a listing to let me use my portable cd player with it while I'm say, mowing the lawn.