motorheaddown

Greetings!

I wanted a little more bass and better treble balance in my sc300 without installing a speaker box in the trunk; so, I decided to replace the rear mids with 6x9s and install an aftermarket amp.

I'm sure there's more than one way to mount the speakers in the rear deck; so, don't take this as gospel. Hopefully, though, it'll be useful to the community by showing one approach that worked for me.

For the installation, I used a 90 degree drill attachment, Dremel tool and cutting wheel, and a bandsaw. Although, I was able to fab one of the plates below with a chop saw and dremel tool; however, it takes a lot longer to do so.

After removing the rear seat, rear deck cover, subwoofer amp, and mids, create a thin cardboard speaker template to mark the template on the rear deck. I suggest making the oval template slightly larger than you need to accommodate sound deadening matting to cushion and cradle the speaker. You'll see why later.

You'll have to cut the oval holes from underneath the deck; so, that's where to tape the template. It's really important to place the templates so the speaker mounting holes are on flat surfaces and clear of any welded nuts from the old speakers or subwoofer amp. Otherwise, you'll never get a nut on the 6x9 speaker mounting screws. Once the template is in place, mark the oval and pilot holes for the new speakers with a Sharpie. Then, cut out the partial oval using a Dremel tool and cutting wheel from below. Also, if you have tint applied to the rear window, make sure it's covered; otherwise, the hot metal shavings from the cutting disk will melt small pinholes in the tint. Afterwards, it should look like this:

Driver side from below


and above. (Be careful of the nitrous bottle lurking in the background! :-P)


The black film is FIPG to cushion plates I created from 1/8" thick aluminum. I used 1/8" plates because the mounting surfaces are about 1/8" below the OEM speaker mounts. The plates will complete the oval support and provide a level mounting surface for the 6x9s.

Here are the plates.


Cut the square plates from aluminum stock with enough overlap to cover the area marked in FIPG. Then cut pilot holes in the rear deck to secure the plates in place. Holes on the forward edge of the rear deck must be drilled from above with a shorten drill bit and a 90 degree drill adapter attachment because there isn't enough room from below. The aft holes must be drilled from below because there isn't enough room to do it from above.

Position the blank plates over the area covered in FIPG, mark the holes from underneath the rear deck, remove the plates, and drill them on a drill press or by hand. Then, bolt the plates in place and use the speaker template from above to mark the material that must be removed to complete the oval. The circular cut is best achieved with a band saw. Once the plates are fabbed, install them and do a test fitment with the speakers. It should look something like this:



Next, create a sound deadening mat template that covers the plates and the holes.



The oval cut-out is 1/4" too small; this is to provide material that wraps around the hole to cushion and cradle the speaker (that's why the speaker oval cut-out is a little bigger than the template). Obviously, you'll need to cut slots in the extra material so it'll wrap around the speaker hole when the 6x9s are installed. The large "tabs" are to cover openings in the speaker mounting surface from underneath.

With the plates bolted in place, use a heat gun to glue the matting in place but make sure to precut all the screw holes in the mat ahead of time. Once the mat is in place, then install the speaker and bolt it down. I used 10-32 stainless pan-head screws, washers, and lock washers:

Here's the final installation:




I reused the OEM speaker pigtails and ran the speaker grommet through existing holes in the rear deck; consequently, no additional holes were required. Also note the slotted tabs around the perimeter of the speaker; this is the quarter inch of additional matting that cushions and cradles the speaker.



The final issue is relocating the subwoofer amp. I elected to mount it underneath the rear deck using the existing nuts and the longest 10mm screws I could find:



I'm still working on the cabling and final mounting, but I'll simply extend the existing subwoofer cable and route it through the rear deck.

Well... that's about it! This is more work than it looks; so, be patient. The most important issue is aligning the speaker mounting holes so they don't interfere with any of the welded nuts under the rear deck. Unfortunately, I got real close on one of the subwoofer amp nuts if you look closely in the last pic.

Good luck!
-scott

lem321

Beautiful job and great write-up!!!

motorheaddown

I decided to ditch the OEM sub and go aftermarket with a 5-channel amp. I found an MTX shallow sub and reused the subwoofer bracket. All I had to do is open some of the speaker mounting holes, and it fits right in! Here's the sub mounted in the bracket:




Next, I had to open up the rear deck subwoofer hole for it to fit. I simply created a 9 1/8" diameter template, centered it (very important!), and then cut out the extra material with a Dremel tool. Here's the mounting from below:


Then, it was a easy to bolt it into place:


Here's the whole deck with 2-way 6x9s and a new sub:


BTW, I went with a 5-channel Picasso Nano amp. It has a very compact footprint and produces a great punch and clear sound.

I should note, the stock rear deck and speaker covers fit over everything. I simply didn't show it in these pics.

Thanks,
-scott

SEIDO

iTrader: (1)

Is that a free-air sub?

Got video of the sound; since u have no box?

motorheaddown

It's not a free air sub, but you'd never know it. The MTX FPR10-02 10" produces an incredible bass when mounted in the rear deck. I could not be happier.

What will a vid show you? Are you simply trying to eye-ball the action of the speaker?

Thanks,
-scott

SEIDO

iTrader: (1)

A vid would show me if it still sounds good without a box

motorheaddown

I can vouch for the sound. However, I contacted MTX, and they do not recommend using the FPR10-02 in a free-air configuration as it shortens the life of the "soft components". In my case, I don't want the reduced space claim or increased weight of a dedicated sealed box. So, I'll use it until it dies and then replace it with another one because the sound is that good for the cost, size, and weight of the speaker.

TyStephens

Since its been a couple years now , how long did the sub last for in the free-air situation?

motorheaddown

It still works, but admittedly I don't run the stereo that often. Most of the time I'm tuning the car; so, the stereo is off.

Thanks,
-scott