Oh, Steve, back in the day, Tampa Bay Auto Sound was building enclosures with hinged doors. I know of 2.
1. My neighbor's friend had a black Escort GT (remember them?) with 4 RF Pro Series 12's. 2 firing forward and 2 upwards, sealed. The 2 were mounted on the board that had a handle so you could lift it up and open it. Why? I assume it was double baffled. Anyway, I remember him stuffing *fiberglass insulation* into the box. lol.
It's the first time I hear the term "it makes the woofers think they're in a bigger box".
2. An old school mate had a 1990 RS Camaro with 2 RF Pro Series 15's. Again, TampaBay Auto Sound used they a hinge. They used the trunk as an enclosure, you could see the brass hinge spine running along from side to side. Flush install, sealed. Looked really nice. The subs were mounted to a double baffle, it was a bitch for him lift the handle too. Lift up the lid and a Power 650 laid on the floor of the trunk.
Anyway, RF & Tampa Bay Auto Sound was the shit back then!
-Frank
-typo