Enclosure design for X6 storage compartment

Here are some pictures of my progress on an enclosure using a Scan Speak Revelator 28W/4878T00 beneath the storage lid of my 2016 X6 F16.

I opted to leave the liner in. My job would have been easier if I took it out. The goal was to get as close to 1.5 cubic feet sealed while leaving enough room for at least one amplifier. There is also a lot of room where the stock amp is.

Madisound recommends a 1.5 cubic foot sealed enclosure for the 28W but says anything over 1 cu. ft. is acceptable. I am too lazy to do the math but I guess I ended up with around 1.35. I'll add plenty of stuffing. I was able to get 1 inch of clearance on the high side of the magnet but since the top slopes, a bit less on the low side.

I think I am close. I may need to sand down a few areas to make sure the enclosure doesn't touch any of the metal frame or secure it to the frame to minimize rattles. I was pretty nervous testing the first fit and needed to take some material off the back high end. A one inch round router bit did the trick. I may take it down a bit more with a sander. No issue since the top is a 1 1/2 inch MDF/Baltic birch sandwich. For some reason the high end doesn't fit flush to the floor.

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Looks good! Well done.
Anxious to see the finished product.

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My system installation was completed Friday by Musicar Northwest in Portland, OR. I had dropped it off Monday and they had the X6 all week.

Musicar humored me and installed the subwoofer enclosure I built and used the MMats amps they do not sell. I did purchase all the other gear from them. I have admiration for the forum members that do most of the work themselves but attempting to install this level of components’ in this car was beyond my comfort level.

The liner in the storage compartment had to be removed in order to fit all the components. Even though Madisound recommends a 1.5 cubic foot sealed enclosure, my installer felt a 1 cubic foot box would work better since a sub is asked to do a bit more in a car. He was able to get the sub to bottom out but he was testing at volumes I would never approach. I think it sounds great but may not have the experience and equipment to notice any limitations. I sure don't notice any and feel I have a discerning ear.

Tough for me to come up with the actual volume of my box. If I take the volume of the dimensions with an internal height of 7.25 inches, add it to the height of a box with 6.5 inches (I threw away my notes and don’t remember for sure) to account for the slope and divide the total by 2, I come up with 1.35. Deduct the driver volume .07? and deduct the notch of around .02?, wild guess, I should be at close to 1.25?

Over all I'm thrilled. The sound, including the bass and sub bass range is much closer to what I am used to in my home 2-channel room than my 335i is using a JL 12W3v3-4 and I think the 335i sounds fantastic. This just takes it to another level. I’m very impressed with the Musicar NW team. They are a great group and do quality work. I plan on getting back down to Portland in a month or so to make some minor adjustments to the driver seat and two-seat tunes if needed.

I only have a few hours of listening in and was driving, had a passenger and didn't really push it but so far so good.