How To: G9 Rear Deck Sub Install

**Team Helotes** · 03-11-2009, 11:57 PM

Disclaimer: This is for info only. It is not my fault it if you screw up your car. This is NOT a novice install.

You also lose the center rear seatbelt and child seat upper rear mounts. I am currently looking for a rear pull style lap belt for the rear.

Here is the step by step way to mount a sub in the rear deck.

Sub Used JL Audio 13TW5

Amp Used Alpine PDX-5

Remove rear seat.
Remove center seatbelt.
Remove rear speaker covers and speakers.
Remove rear deck carpet cover.
Remove upper child seat mounts.
Use the carpet cover as a pattern to made a rear deck out of ½” MDF.
Test fit rear deck and adjust sizes as need.
Find center of rear deck and use a Sharpie to layout a 14” x 14” square. You can use the centerline from the rear defroster in the glass to help find center.
Use a piece of cardboard to cover inside of rear window. Pull back or remove the trunk liner. Use a die grinder with a cut off wheel to cut out the hole.
Mark and drill 4 - ½” holes about 2” out from the hole on each side the hole in the rear deck.
Build a speaker box out of ¾” MDF to fit your sub. Mine needed .65 - .80 cubic feet of air space. My box is 14” x 24” x 6” outside for a total air space of .73 cubic feet.
Cut a piece of ¾” MDF 13 ¾” x 13 ¾”
Line the box up and center it below the hole you cut in the rear deck. Use a couple of drywall screws through the deck to hold it in place.
Once you have it where you want it take the MDF cut is step 11 and glue it and brad nail it to the top of the box in the hole cut in the rear deck.
Mark 4 holes to holes you drilled in step 10 they should be into the top of your sub box.
Remove the box and drill the holes you just marked. Drill them 5/16” on the inside of the sub box install 4 - ¼”x20 T- Nuts in the hole you just drilled.
Place ½ MDF deck in car and make 4 sub mount hole and speaker cutouts from the bottom.
Cut out the speaker holes to fit your speakers to you 6x9s and drill the bolt holes ½”
Install the ½” MDF rear deck and sub box with ¼” x 20 2.5”long bolts with fender washers on the top. The oversized holes will allow you to center up the sub box.
With everything bolted up use the carpet to make you another read deck out of ¾” MDF. When you get to fit like you want use a 2” Forsner bit to drill out a recess so the bolt head and fender washers will sink into the ¾” upper deck.
Cut out your speaker holes in the upper deck allow the hole to be about ¼” – 3/8” larger than the speaker. This will give you room for the vinyl or carpet.
Use a router to round over the top edges of the upper deck.
Cover the deck with vinyl.
Paint the back edge of the ½” MDF deck flat black so it does not show through the glass. Paint the box for the trunk black as well.
Install everything mounted the amp on the bottom of the sub box.
Now you have a setup as cool as mine.

**therev** · 03-13-2009, 11:57 PM

Looks quick and easy...hardest part is making the box the correct dimensions, but all in all looks mint!! Great Job 5 stars!

~Gabe

**Team Helotes** · 03-14-2009, 12:15 AM

Building the box was the easy part box only took about 15 min to make.

**Gtsnapper** · 03-14-2009, 11:41 AM

That looks great. Nice work!

G_RIDE · 03-14-2009, 02:38 PM

that came out clean. i was wantin to do somethin similar to that but i was told by someone at car toys that it wasnt a good idea cuz it would cause to much rattle on the rear deck. is that tru, have you experienced that yet?

**Team Helotes** · 03-14-2009, 05:05 PM

Originally Posted by G_RIDE

that came out clean. i was wantin to do somethin similar to that but i was told by someone at car toys that it wasnt a good idea cuz it would cause to much rattle on the rear deck. is that tru, have you experienced that yet?

No rattle here.