Hah hah , I remember guys hooking up 8 track players in their cars and wiring big old speakers to sit in their back windows so they could play them extra loud.
Those were the kool guys.
I had Jensen speakers in my 1975 GMC pickup. I built wooden boxes that could fit behind my seat in the cab. However, they had long enough speaker cables on them so you could put them on top of the roof.
This came in handy when you went to the drive in during the summer. I would pull in backwards. Then we would sit in the back on the truck on lawn chairs with a cooler for beer and a footrest.