A busy day today investigating doors and speakers, and finding someone has “been there before”.
Most important thing first, I tightened this screw two and a half turns, its friend at the other end of the passenger door handle only needed half a turn to reach 7.5 N.m, and now the door handle doesn’t flop about or let water into the car.
Taking out the inner trim and ‘door unit’ revealed missing hex head self-tappers and already broken trim clips.
I need some of these, ten of each should cover future breakages and losses.
And the tweeter plug is so mangled it was much quicker to unscrew the unit from the trim panel than work out how to unplug it.
I measured the Free-Air self resonance frequency Fs of the bass unit; it is 80Hz. Therefore it is incapable of any useful bass regardless of what cleverly designed enclosure it might live in. The door resonance of 50Hz is actually helpful!
I’m now thinking about the Sub that was mentioned a couple of days ago, cheaper and much quicker than tracking down some decent speakers with Fs of say 40Hz. Crossing over at about 85Hz (an Alpine preset) would allow for quite nice fine tuning if I can believe the In Phase data sheet.
I also finally got around to popping bits of silent-coat on the outside of a door with a sheet of newspaper to protect the paint with lots of mini magnets to hold it all on place. The doors-skin sounded better, but resonance was still close to 50Hz. Thus no point in trying to lower resonance this way, especially since access inside is limited by crash-bar, stiffeners, window-mech etc. I forgot to take any pointless pics here!
However two slices of silent-coat cut into suitable smaller bits to fit inside the outer skin of the passenger door have damped down its “tinginess” to more of a dull clunk when I tap it. Alas no pic here.