Interesting Sub Placement

[anthony303]

I have seen a couple pics of cars that have their sub firing through the passage thats in the trunk. It faces into the car and looks pretty cool when the armrest is down. What does this do for sound quality, is it better worse, or not really a difference? and for those of you who may have experience with this, does it take a lot of work to fit it and make everything look nice a neat?

[El Presidente]

it lessens SQ. Short explanation is the way bass expands and reverberates in the cabin is not the same as the trunk.

As for fitment, its not hard getting everything to fit well, it just takes careful measurements and cutting. The last box I built I didn't pay attention to where I measured and when it came time to test fit, it was off by about .5". Had to take it all apart and rebuild it, after cutting off 1/4 from each end. After that, it fit like a glove. (see post with pics of komodo9s install).

[PMB]

This was easy, The sub is a Rockford Fosgate P210S4 (10"), but a P212S4 (12") would work better. I am currently playing with a P115S4 (15") but this causes some insatllation problems as the diameter of the sub exceeds the ski hatch hole.

Instructions.

Remove the piece of trim in the trunk that covers the ski hatch. From the front use a length of 2X4 and a mallet to knock the metal out of the hole. This comes out with 2 or three sharp hits.

Use the piece of trim from the trunk as a template and mark out it's size and shape on a piece of 3/4 inch chip board. You will notice in the middle there is a small hole, mark this as it will be useful as a guide when you need to mark where the sub is mounted. Cut the shape out with a jig saw. Check to make sure it fits.

The RF subs come with a trim piece which is exactly the size of the mounting hole. Mark this carefully (using the "small hole mark" as a guide, and cut out.

Cover with carpet both sides. Mount sub and amp. The rear speaker output can act as your input to the amp. You need to run a wire for remote turn on of the amp.

When you mount it in the car drill 4 holes in the flat bit of the ski hatch (you will know what I mean) and use bolts with spring washer. You will need to tighten them regularly at first.

With regard to sound quality, the piece you cut out which is the same size and shape as the back seat of the trunk acts as a baffle board, thus then uses the entire trunk as the sub box, but you need to be careful when choosing the sub Look for one with a high VAS and an XMAX of 8MM or over. A sub of high power handling is recommended. When you mount a sub in a box the box is always tuned to a specific frequncy which becomes a dominent and sometimes monotonous sound. The bigger the box the lower tha frequency. With a box the size of a bmw trunk this does not happen but the sub will not always work it's best. Do you lose out on SQ? I dont think so power handling and SPL yes, possibly.

Any questions please ask. I will post pictures of the 15" soon