911 SQ stereo install with custom sub enclosure

[willtel]

Now that I almost have my stereo install completed I thought I would put up some pictures to see if it may help anyone else with their car.

When I purchased my car it had a non factory Sony CD player and some upgraded Pioneer 4" door speakers along with the 4"x6" speakers in the rear deck. The rear speakers were destroyed by the Texas sun and the fronts were barley audible above 30mph. I removed the head unit and drove the car for nine months with no radio as I planned what I was going to do.

My installation consists of the following:
Denon DCT-100 CD Player
Phoenix Gold XS6600 6 channel amplifier
1 pair of Aura braxial MR62 speakers for the doors
1 MB Quart 10" subwoofer

I started by installing the speakers in the doors. The factory baffle was removed from the door panel and a spacer was made from a nylon cutting board. This spacer was screwed to the sheet metal door panel using three machine screws and locknuts, it has several reliefs cut into the back to allow it to sit flush on the panel.



After the spacer was installed I used some sound deadening material to cover the area near where the driver will be mounted. I could have covered to whole door but I don't want to remove too much of my cars character with sound deadening.



Next I reinstalled the leather door panel and screwed the driver into the nylon spacer through the door panel. There are 4 screws holding the driver and they must offset the other 3 holding the spacer so they don't collide. The 4 screw holes in the leather panel are the only permanent modifications I have made to the car.



I choose the Aura MR62s after reading about them on car stereo forum. They have small neo magnets and the basket has a deep taper so it isn't necessary to make the factory speaker hole any larger. They are no longer in production (haven't been since 1998) but I was able to find a NOS set complete in the box for well under $200 dollars on the same forum's classified section.

Since the tweeter is mounted on a bridge over the midbass driver there is also no need to cut an additional hole in the door panel like you would with a traditional component set.

You can find more info on them here, http://www.aurasound.com/public/discontinued/frameset2.html

The speaker grill in place.


Door pockets reinstalled. The tweeter just peaks over the top of the pocket.


Once the door speakers were installed I had to select a head unit. This wasn't easy as I wanted something with muted looks and excellent sound quality. I finally came across a new Denon DCT-100 on eBay that fit the bill perfectly. Denon only sells car stereos in Japan so these are pretty tough to get, it wasn't cheap but I couldn't be happier with the looks and sound. The illumination also changes to green and it has an RCA auxiliary input I use for an iPod. The head unit install was pretty straightforward so I didn't bother with pictures.



Now that I had a source and some speakers I mounted the amplifier in the trunk on a temporary board attached to the spare tire mount. No photos because it is currently ugly, I'll sort out something more permanent later.

With the mids and highs taken care of I now needed a subwoofer. I did a lot of research on 911 subwoofer enclosures and nothing I found exactly fit. I wanted a sub that was easily removable and had good output from a single driver without looking like a coffin in the back seat. After some searching I came across a used pair of MB Quart subs that matched up well with the power I had available and had a fairly shallow mounting depth of 5". I purchased both the subs with the intention of only using one. Once they were delivered I decided the most logical place to mount it would be in the rear passenger footwell inside a fiberglass enclosure.

To create the enclosure I removed the piece of carpet in the rear footwell and masked off the entire area with 2 layers of 2" masking tape in alternating directions. Once the area the enclosure would cover was masked I put a layer of aluminum foil down and pressed it into the footwell with a bunched up towel. The foil adds a moisture proof layer on top of the tape and will help the fiberglass mold release when the resin has set. I did two layers of chopped mat fiberglass in the car and then pulled the mold.

It came out looking something like this.


Before the MDF ring in the photo was added I put 3 more layers of fiberglass down for strength. Once those layers cured the MDF mounting ring for the driver was glued into to mold using scrap wood at the angle I wanted the speaker to sit.

Once the driver location was set I trimmed the rough edge of what will be the bottom of the enclosure.



Now the shape of the enclosure is pretty much determined. For the next step I stretched a fleece material over the ring and glued it into place on the edges using thick CA (hobby super glue) and some CA cure accelerator.

After trimming the fleece it looked like this.

[willtel]

This layer of fleece was soaked with fiberglass resin to provide a base to lay the rest of the fiberglass mat on. I think I ended up with 4 more layers of fiberglass before I was happy with the strength.

Here the fiberglass is complete and the driver is placed in the enclosure.




I then carpeted the enclosure with latex backed carpet and spray adhesive. I also mounted two speaker terminal binding posts into the enclosure to allow it to be easily removed from the car without tools. The speaker wires were terminated with banana clips and covered with color coded Techflex sheathing and shrink wrap.





I then mounted the driver with stainless hardware for a little contrast and put the completed enclosure in the car for the first time. It literally looks like it grew there.



In this picture the seat is several inches forward in the tracks, this is the only time the binding posts can be seen.



When the passenger seat travels back to it's stops the seatback just rests on the drivers surround. Sliding the seat up 3/4" to gives it plenty of clearance. I'm 6'1" and the passenger seat will go back further than where I keep my drivers seat without any contact at all, in this picture the seat is as far back as it will safely go. The auxiliary input cable for the iPod is also coiled in the passenger footwell.





With the new stereo and speakers installed the passenger compartment is a very nice place to be. Although I still have plenty of tuning to do the sound really is incredible. The Aura speakers pump out plenty of midbass while the tweeters have a nice smooth tone. The sub output is exceptional and more than enough for the car and blends nicely with the mids.

All I have left to do is to neaten up some cables and sort out a permanent and attractive amp rack for the trunk. I'm open to suggestions for that one.

[Canada Kev]

I never knew how to make a fibreglass box before. Learn something new every day. Thanks.

The red interior look spectacular, by the way.

[village idiot]

Nice work! I'm currently looking for some quality speakers to replace the Polk audios in the doors now. Any suggestions??

I'm pretty disappointed in the sound quality as the left front speaker buzzes quite a bit like the surround is torn(it's not). And there's zero bass. Hell, the 2 speaker setup in my Civic sounds better

[spence88mph]

Far out, what an amazing, fresh approach, car looks sensational too.

You could sell those enclosures, they're the best solution I've seen by far.

[tomphot]

willtel

PM sent

[imcarthur]

Great solution. A fiberglass enclosure for the woofer is the best method. I didn't with mine because I knew (being the klutz that I am) I would get resin everywhere.

Ian

[nineball]

naaa it is easy to get around that. 2 layers of painters tape in opposite directions a few inches bigger than the size you want the base to be, a layer of aluminum foil over that and a tarp or two covering the rest of the interior and you are golden. that's how i did mine.

new audio install

[RWebb]

thx for posting the enclosure fab instructions

but, it looks awfully small - is it sealed or is it a ported alignment? and what size space did the manf. say to use?

[willtel]

Originally Posted by RWebb

thx for posting the enclosure fab instructions

but, it looks awfully small - is it sealed or is it a ported alignment? and what size space did the manf. say to use?

It is sealed, I prefer the response of a sealed enclosure to ported. I think the manufacturer recommends .65 cubic feet for each sub, I probably have closer to .50 but I have no complaints about the output.

[RWebb]

as long as you're happy

BTW - it is not the output (amplitude) but the frequency response that is fouled up - wrong "Q"

[Rob B]

Nice work! Here is a link to my sub enclosure, also in 'glass, that I made to fit in the rear seat pan .Another sub woof install idea-photos

[heiltrading]

did both sides DVC 8", pretty much way to loud!

[nineball]

Originally Posted by willtel

It is sealed, I prefer the response of a sealed enclosure to ported. I think the manufacturer recommends .65 cubic feet for each sub, I probably have closer to .50 but I have no complaints about the output.

you can always add polyfill to a small sealed enclosure to trick the sub into thinking it has more airspace.

Parts-Express.com:*Acousta-Stuf Polyfill 1 lb. Bag | sound dampening sound polyfill fiber enclosures enclosure dampening cabinet_damping

[RWebb]

"Mid-Fi, not Hi-Fi" sez one comment

Ian - any comments on this?

[imcarthur]

Sure. nineball is referring to the isothermal theory.

For a somewhat learned discussion I ran across this:

Home Theater Shack

I know that cabinet damping is part science & part trial & error - even in the professional world. A recent mod on a model involved ripping out some light foam insulation on an internal brace which had a dramatic impact on the upper midbass.

The pictured product sounds fine but who knows if it is any better than cheapo pillow fill? Focal uses foams + polyester fill in most models. Different types & thickness.

Ian

[RWebb]

thx - I thought every manf. used some kind of fill (not Magneplanar, obviously...)

not sure why that would be characterized as Mid-Fi...

[sc_rufctr]