[D-e93]

Car: 2009 e93, I.Drive, HiFi, No ski-hole pass through from factory.
Speaker: Alpine TypeR 1242d.
AMP: MRP-M500 - connected@4ohms
Box type: Sealed 1.0Cu
Connection type: T.tapped
Tutorial Used: http://www.e90post.com/forums/showthread.php?t=87130. Except the remote is coming from the thin black cable in the back, no need for LVT2 module.

Very weak bass output + "Ski hole pass through" = Custom speaker box for the Ski hole .

What a brilliant idea, I though I was going to go to ebay and find one instantly, not really. I was going to have to build one myself. Hadn't seen anyone using a box through the ski hole right to the back of the seat for a convertible. So Im off to the drawing boards. The first mocks where of a ported box but I decided to go sealed, saves me space and more detail.

My car originally didnt come with the skihole pass through, but i was able to remove 2 panels that opened it. I can buy later on the 2 pieces needed to make the ski hole pass through look stock. http://parts.bmwofsouthatlanta.com/s...ssembly=259155 .

The custom box:
Everything was made from 3/4'' MDF. The first piece you cut is the bottom piece that looks like a "T" for the floor. Then go on to cut the half octagon. There are 5 pieces, first cut the two walls that consist of 2 pieces. Dont do the top piece, this will come at the last. These pieces you can do one by one and sand them till its right. One thing i noticed is that the measurement you will get from the opening in the back is not the same size as the opening into the cabin, it gets smaller, so dont glue anything just yet and try not to overcut as much as possible. You will build the remaining back side of the box. Then at the end you can cut the top piece while you actually test it in your trunk space to make sure all lines fit flush. You will have to be very precise, because for a 12'' woofer the opening barely makes the top and bottom diameter of the woofer. On the inside of the box, i also had to sand some of the top and bottom walls so that the subwoofer fits nicely. Also note that there is an angle in the back seat, the woofer sits at about a 10 degree angle. I also put an extra 3/4 wall in the back wall of the box since i noticed that this is where most of the speakers pressure was being pointed at.

The Amp connection:
http://www.e90post.com/forums/showthread.php?t=87130. Except the remote is coming from the thin black cable in the back, no need to buy an LVT2 module.


The verdict:
Alot of the mudiness is gone. The bass sound is much cleaner. No more crap sounds when you raise the volume and want to feel the beat. Much better quality through all genres and formats. I have the crossover point of the amp at around 65hz, gain at 40%, with the JLAudio W6. At some levels, the bass in my opinion is too much. There are no major rattling noises inside the car. With decent volume turned up, on the outside, with the doors closed, the bass is hardly noticeable, definitely no license plate rattling. Stock tweeters still sound dull but I think the subwoofer has cut some of its harshness.

This is my first custom box and my first amp install, so im still working on some details.

Tips:
Pre-Drill everything.
Lossen up the joints and try to fit in before gluing anything.
Used Titebond glue for joints, do not use liquidnails!.
Crank this box up in your home stereo to test it for leakage and sensitive points.
Using a JL Audio W6, insert some poyfill.












10/15/2012: Installed W6.
The difference between the Alpine and the W6 is noticeable from the second you hear it. The Jl has a much noticeable smooth warm texture.

8/3/2013: Installed 600/6 , front jl components, technic harness.
Awesome quality!

11/2014: Installed FiQ 12" with a Crescendo 1500 and bought Seas twitters from Madison shop.

04/2017: Installed Dayton AMT Tweeters, much cleaner less-fatigue than Seas

04/2019: Installed More 4" Shallow

08/2019: AudioControl D6.1200

10/2019: Installed Morel 8" Shallow

[KingCC]

Nice... great idea!

[Xradeon]

Hey, inspired by this setup I just ordered a JL 12 w3v3-2 sub and a R2-500X1 Rockford Fosgate mono amplifier. I'm just planning to make the box a little bit bigger on the back side.

[Ali-E90]

I think the e93 ski pass would lend itself well to IB like it does for the other models... could save the limited trunk space you have and run IB instead.

Here's my sedan, yours would look diff, prob need a smaller driver, but can perhaps achieve similar results.

[D-e93]

Hey thanks for posting. Im still loving this setup. It was totally worth the effort. Deep, tight, SQ bass..

[Ali-E90]

Originally Posted by D-e93

Hey thanks for posting. Im still loving this setup. It was totally worth the effort. Deep, tight, SQ bass..

what are your thoughts as you went from the W6 to the FI?
Still using polyfill, or does the new woofer not need it?

It's threads like this that continue to help us, even after 8 years! Cheers!

[D-e93]

The JL W6 is a good sub that got the job done but eventually its coils got burnt, not sure what happened there, so I decided to go with something more than its RMS.. This FIq handles the lows better all around. Its not a fair comparison just based on each speakers RMS. I could never crank that speaker all the way. A little over engineered so i wont run it at full capacity. I removed the poly-fill for this one and just have the inside walls treated with dampening material. The amp (1500W) is cranked to about 25% and its sounds phenomenal.

If I were to do it again, I would make the box a little bigger to fit just right and the back-wall slanted. Cheers!