The connection from cable into earcup should be very firm. I worked with difficulty and a lot of pressure (perhaps 40 to 50 pounds of pressure) to get the cable all the way in. When you look closely where the plug is inserted, you see two "bands" around the earcup - the inner band about 2mm wide and the outer band about 5mm wide. The plug should be fully flush with the inner band and actually about 1/2 to 1mm into the outer band. If you remove the plug and reinsert it, you should get a very substantial click. So yours may not ever have been fully inserted. It takes enormous effort.
The NC works exactly as you describe. That algorithm was designed originally for jet planes, to suppress the jet engine rumble but allow you to hear people talk when close by. The Bose QC2 was designed like that, but apparently Bose designed the QC15 differently, to suppress all noise. Suppressing all noise on a jet may be OK in most cases, but is considered dangerous for pedestrians and bicyclists out of doors.
Whoever designed the sound signature is a genius, hands down. It is extremely difficult to get a strong bass that doesn't muddy the midrange, and yet there are no noticeable recesses in the range between bass and mids. This is in active mode with bass reduction (and still *very* bassy).
The NC works exactly as you describe. That algorithm was designed originally for jet planes, to suppress the jet engine rumble but allow you to hear people talk when close by. The Bose QC2 was designed like that, but apparently Bose designed the QC15 differently, to suppress all noise. Suppressing all noise on a jet may be OK in most cases, but is considered dangerous for pedestrians and bicyclists out of doors.
Whoever designed the sound signature is a genius, hands down. It is extremely difficult to get a strong bass that doesn't muddy the midrange, and yet there are no noticeable recesses in the range between bass and mids. This is in active mode with bass reduction (and still *very* bassy).