JT Si
Senior Member
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- #1
Mounting 5-1/4 speakers in the rear coupe deck isn't impossible, or even very difficult. It's mostly just a lot of work to custom-fabricate mounting adapters.
One stipulation I had was I refuse to make permanent modifications to the car's chassis. This meant I would not expand the rear deck holes. Due to very tight clearance of the speaker basket to the deck cutouts, I had to modify the speaker slightly. I bent the wire mounting tab down so it would clear the cutout rim. This area is where I apply liquid electrical tape to later.
At first I thought I could carve out the OEM speaker baskets, but they had holes and were very, very fragile after removing all the material necessary.
I settled on making adapters, and ended up choosing 1/2" PVC sheeting in gray I ordered from Amazon.
I also bought a Lennox 4.5 inch (114mm) hole saw to cut out the speaker mounting holes, as this was the exact size of my Alpine S-S50s and many other 5-1/4 speakers. I wanted to ensure I had a perfect circle and that I would not remove too much material trying to cut it with a jigsaw.
I also had to buy a jigsaw, but the important thing is the blade selection - Bosch T102H clean for PVC jigsaw blades. I could cut as fast and long as I wanted and it did not melt the PVC and it left a nice, clean smooth cut finish.
I marked out the general size and shape and the center and cut out the holes first with the Lennox hole saw.
I then cut them out in a large oval shape. After several cuts and test fits I finally got them to the shape that would fit with the least material removed.
I pre-drilled 3 holes for the speaker and mounted it in the bracket, and dropped it into place. I then marked where the OEM bolt hole is to drill out the 4th speaker mounting hole, which would use the OEM bolt to also mount the bracket.
After getting all 4 speaker holes drilled, I then dropped the bracket back into place and partially installed the mounting bolt. I then marked from the underside where the two square holes the OEM bracket fit into were.
I drilled holes out in the outer corners for the two square holes.
After getting all the holes setup and double checking they were aligned correctly, I lined the bracket with 1/4 x1/16 foam strip to seal the speaker to the bracket and the speaker to the car.
The last step was to line the edges of the rear deck that were very close to the tinsel leads with liquid electrical tape. 3 coats and it was ready to go.
All in all, it didn't give much of an improvement because the signal to the rear sucks. If you're going to install better amps and signal correction, or if you are going to install the Axxess DSP interface that bypasses the touring amp, it would be very worthwhile.
I suppose if you have a model without the upgraded stereo you can probably get a decent signal to the rear by disabling the DSP in the head unit.
On a side note, I de-soldered the coaxial tweeters because I installed Alpine 1" tweeters into the rear deck cover and wanted the 5-1/4 woofer to receive full power on its dedicated channel.
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