I've seen a lot of things done with woofers in my day; many of which shouldn't even be legal! But I've never seen a woofer with a clear plastic dust cap. Pretty neat, actually.
These Technics SB-G910 monsters had a LOT of bass, but that's about all I can say for them. Lightweight cabinets shook and rattled when the volume was cranked, but that's what classic house speakers are supposed to do - right?
Notice the latex-gloved hand? Yes, we always wear latex gloves when handling Technics speakers. Don't you?!?
Have any experiences with Technics house speakers from the 80's? Chime on in.