Mercedes SLK World banner

Status
Not open for further replies.
1 - 7 of 7 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #1
Today marked the beginning of actual production on a custom subwoofer box for my "new" 170. Been collecting parts for a while, and today we kicked it off.

The car had an aftermarket head unit when I got it, running as far as I can tell to the stock speakers, which are not bad, but lacking on the low end of things IMO.

After careful consideration of the options, I decided to replace the spare tire with a 12" Kicker and amp. It has officially been 15 years since I have needed a spare tire, and I pay for roadside assistance anyway, so if it really comes down to it I can easily be towed to a tire shop. The goal here is to get really great bass going, and not loose any more trunk space than I absolutely have to.

Due to the unusual shape of the space I am going to be using, I have opted to build the lower portion of the box out of fiberglass, and the insides and top will be MDF. I have elected a bandpass design, which will mean two separate compartments within the enclosure, with the "back" of the sub (bottom) having a port that will come up to the surface of the box. The very top of the board will be MDF that I will put some kind of carpet on, and it will extend around the entire floor of the trunk as best I can, so as to function as the new floor of the trunk.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #2
So lets get this party started.

First things first, made sure I had spots to run the cables. Wasn't too hard, this is just behind the drivers seat:


Once you get past the fabric behind the drivers seat, there is a pretty clear shot back to the trunk, with a panel you can easily snake the lines under:



Managed to get the cables all the way to the head unit without actually removing any panels in the front. All just peel and tuck: (Side note, whoever put this head unit in did an awful job on the wiring. May want to rebuild this bundle later)
:


Here is the lines at their final point where the amp will go, on that little shelf on the left of the trunk. Again, managed to route all lines without removing any panels, just loosened them enough to run a line snake around where I needed to go:



Blocking off the right side of the spare well, since I don't want to build the box right into the PSE unit down there:



Masking:



Masking, little MDF border between the sub enclosure and the amps space:



Couple layers of fiberglass. Not going too thick here, because the load bearing aspects of it will be taken care of mostly by the MDF on the sides and top:




Whew, long day! With any luck I will continue this week building the upper layers of the box.
 

·
Registered
Joined
·
570 Posts
Looks good! Reminded me of my first MDF fiberglass enclosure in a 95 civic hatchback when I was a teen, I got a little carried away with the resin :) I did one sealed box with free air subs once and put in plenty of polyfill and it actually worked out with a nice thump ( I was surprised ). Looking forward to the rest of the pics.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #4
The goal here is to do it without polyfill, but to actually have the proper sizing for the sub. So far it's looking good. Once the plexi dried a bit today I did some packing peanut style volume calculations.

Determined with the spare cavity, and going 3 inches up from the original trunk floor to the new floor line, I will have about 2.75cu ft. of air in there, after all things considered. The face of the sub will be about 8 inches up from the floor of the plexi. The driver is almost 7 inches tall, so cutting it close there but an inch ought to keep things from bumping where they don't belong.

Anyway, so far the calculations all look like I should get acceptable volume at acceptable freq:
 

·
Registered
Joined
·
14 Posts
Discussion Starter #5
Had some more time to work on it today.


First things first, get the fiberglass cut down to size:



Next, get the inside panel made. This will separate the two sections of the sub, and will also hold the weight of the sub:




Cutouts for the sub, and also for the port that will passthrough the upper sealed portion of the box:




Its not time to actually install the sub yet, but just to make sure it all fits right:



All taking a bit longer than I would like, but I'm blazing new trails here so its all a learning process. Also done tonight, but not pictured, was the very interesting job of adding some fiberglass and sealing compounds to the INSIDE of that box all around the edges to mate it up against the lower fiberglass portion nicely. Interesting work, done mostly upside down with my head in the subs hole, or done from above with a mirror reaching in. It's not pretty in there, but hopefully the corners all seal up nicely, we shall see when it is dry.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #6
Got in a little work today, not as much as I would have liked.

Finished routing the wiring, the only thing left in that regard was the power. Took out the kick board in the passengers footwell (didn't get a picture) and found a wire bundle I could chase up through the firewall. It brought me into the relay box that has the K40 and others. Installed the fuse for the amp power in the same box as the K40, and snaked the line out here without having to do any drilling at all, so quite happy with that:



Got the sub and amp actually attached with their proper hardware today, and got it all wired up and tested. Everything works well, and even without the top portion of the box it is sounding fantastic, hope the sound quality remains or improves with the finished product:



Just got started cutting out some of the parts I will need for the upper portion of the box, and had to call it quits. Promised my little girl we would go see the Lego movie today!
 

·
Registered
Joined
·
14 Posts
Discussion Starter #7
Finished it up this weekend!!

Setting up the upper (sealed) portion of the box:



Getting the new trunk floor ready. Port passthrough cut out, and an access door into the non-sealed section where the amp sits, so I can re-wire, or adjust settings as needed without uninstalling the new floor in the future:



Installed, with the access door open:



All finished, and closed up. Need to put some kind of light mesh over the port to prevent objects getting in there. That port goes all the way to the bottom, and will be a real pain if anything gets in there. Other than that, and perhaps some carpet lining the port walls to make it look nice, we are DONE:




Not going to post a video with an attempt to demonstrate the sound, as those are really not capable of properly demonstrating the point. That said, I'm quite happy with the results!
 
1 - 7 of 7 Posts
Status
Not open for further replies.
Top