Finally got my front door speaker install pretty well wrapped up last night! It took about a month, 2 prototypes of a custom MDF spacer ring, and lots of brainstorming to get something to work the way I wanted.
I started with Infinity 6032si 6.5" coax speakers, which are supposed to be a shallow mount model. They aren't shallow enough, by about 1/2" as they contact the window rail inside the door.
I added some Fatmat sound deadening to the outer door skin, covering about 20% of the panel, and some on the inner skin where I could, including the front of the door where the speaker actually mounts. I retained the OEM plastic door liner over top of the sound deadener.
I was looking for a solution that would retain the factory speaker grill, and as many know this is tough as you need to open up the hole in the door card for a 6.5" speaker. I needed something to bring the speaker out from the door to clear the window rail, but that the door card could still go back over. I looked at various plastic speaker rings, but couldn't find anything that would work.
My buddy has a new router, and a sheet of 3/4" MDF, and undertook to make a solution. 1st test fit showed that the original design was not going to cut it. Back to the drawing board, and we had a winner! The final design sits down in the sunken flange the OEM speaker mounts to, and uses the OEM speaker screws to hold it into the door panel, we had to countersink the ring so the screw heads would sit flush where the speaker sits. Where the speaker sits we had to clock the speaker 45 degrees so the screw holes are evenly spaced, and reliefs were cut for the speaker "ears" around the screws, as opposed to cutting the ears off the speakers. The speaker mounting surface is routered into the ring so there's an MDF lip along the outside edge of the ring. We then drilled pilot holes through the spacer and into the door panel, and used self tapping screws to sandwich the spacer ring between the speaker and the door panel. The finished spacer rings were painted with spar varnish to waterproof them. I soldiered the factory speaker leads to the new speakers, so you can use the factory connector to remove them in the future.
My buddy has some better pics of the spacer ring he's going to forward me that shows the dimensions
Moving on to the door card, we confirmed the factory hole is perfectly spaced over the hole in the door where the speaker sits, then used the spacer ring to trace the shape on the back of the door card, and used a small router bit with the depth set to about 1/2 the thickness of the door card board, and etched out the shape of the new hole. Then we were able to break away, and peel off the vinyl the extra material we wanted to remove, leaving the vinyl intact, and a new hole that would fit over the speaker spacer, so the vinyl was able to take up any additional height beyond the level of the door card board, which is minimal. We then trimmed the vinyl back to clear the speaker foam surround, and the door card went back on.
This is where it sits for now. The plan is to listen for a bit, and decide if I want the speaker's +3db tweeter gain switch set to on or off, which is accessible on the tweeter of the speaker, and then silicone the grills, with the tabs ground down, directly to the vinyl face of the door card, so they are a part of the door card going forward.
I've seen some other installs where people cut the door panel into strips they fold forward/flat and mount the speaker to that to gain the clearance they need. I don't like this method as you're mounting the speaker to a flimsy flap of metal, this method is much more solid, and should hopefully transfer any mid-low range the speaker is able to generate much better.
I've only listened briefly sitting in the garage so far, but it's already light years ahead of the very tired, 22 year old units I replaced!
I'm hoping we can come up with a similar solution to mount another set of 6.5" coax in the rear doors without having to cut metal, but we'll see when we get around to having a closer look. I expect I'll need an extra set of front speaker grilles for that project, so if you have a set in grey, please let me know.