MyE28.com

Until if and when I get to building a proper 10" forward firing sub/box mounted in the trunk, I am thinking of one under the rear seat as a temp solution. 
Or perhaps a longer term solution depending on your opinions.

Do you like how yours performs?
What size?
Good enough?

As I've mentioned in other threads, when I owned my last e30, I had installed a "Lukebox" made by a forum member that bolted in the trunk to the sheetmetal behind the rear sear backrest. There was an opening in the e30 behind the rear seat armrest that conveniently allowed a sub to fire through the back of the rear seat into the car. The end result was the best stereo system I've heard in any car, newer or older. I may make my own for my 535is, but maybe not.

TIA!
 

I've made two:

Here is version 1. It was OK. Sounded better than it looked.
https://share.icloud.com/photos/0ad_E6d ... K4wlHzCR-A

Here is version 2 with a larger driver and a larger ArcAudio amp It's better and I have no real complaints, although it does struggle a bit with one passage from The Planet Krypton from IASCA competition tracks. 
https://share.icloud.com/photos/098pa7M ... KTes-W0cZA
If I can get a tuning session in, I'll post the response curve. 

If I find time and money, Im going to take another run at getting that JL monster to fit. 
https://www.jlaudio.com/pages/tw5v2-car ... s-overview


 

I made an under the rear bench box about 20 years ago for my original '86 535i to accommodate a 10" sub on the driver side. Pulled it out after the car was totaled. Actually came across it the other day as I was organizing parts in boxes. It was MDF and then the bottom was many layers of fiberglass formed to the contours of the floor to maximize volume along with a damping material to give the surface some weight. If I were to make a new one I'd try an open bottom design and use a nice gasket to get a tight seal against a well damped floor and see how that works out rather than deal with sealing off the bottom with fiberglass.

On the particular sub I had, the volume was possibly a little small for a 10" so a modern 8" is probably a lot better option. Never really worked out the kinks and dialed it in before the car got totaled unfortunately, but seemed like a solid approach unless you need to rattle your skull.

I originally tried a 12" box in the trunk that my Dad had laying around but it was very obvious the E28 trunk is well sealed and I didn't feel like cutting holes in the backrest or below the rear window to make that work.

I have an under the FRONT seat, active, low-profile subwoofer. It is tunable in many ways and I made it sound very good. I am not replacing it with anything any time soon.

szacsi72 wrote: Jan 15, 2025 4:02 AM I have an under the FRONT seat, active, low-profile subwoofer. It is tunable in many ways and I made it sound very good. I am not replacing it with anything any time soon.

szacsi72 wrote: Jan 15, 2025 4:02 AM I have an under the FRONT seat, active, low-profile subwoofer. It is tunable in many ways and I made it sound very good. I am not replacing it with anything any time soon.

Sorry guys no pictures with me, but this is the model: Caliber BC110USP 10
https://www.calibereurope.com/en/produc ... usp-en_gb/


It's nothing special and definitely not audiophile worthy, but it is tune-able, has an all-aluminium casing, and sounds pretty good. I'm thinking of fitting one for the E39 (daily) too. Just put it under the seat, connect the wires and go..


 

6" or 6.5" Bazooka tube works and sounds great to me!

Yes, I like it.




 

Has anyone put any of the infinity basslinks under the rear seat? If so how did it sound?

topher800 wrote: Jan 25, 2025 10:46 PM Yes, I like it.





 

I have an 8" shallow mount unit from Pioneer that I've had for about 10 years now. It provides plenty of bass for my taste (sometimes too much!). Someone from the forum shared with me their own box and after I built a cardboard model of it I tweaked it a little bit. I've had my sons sitting in the back seat for years without any issues. I can't find a picture of it but I still have the drawing of the box in Google drive. On the passenger side I have the 5 channel amp with the crossovers for the Infinity component speakers on the back.

I’ll be going the same route intially at least.
 

Etip wrote: Jan 28, 2025 4:00 PM

topher800 wrote: Jan 25, 2025 10:46 PM Yes, I like it.


 

Hey. Is this a custom or preFab box? If Prefab, who makes it/what model is it? I'm in the process of putting together a stereo for my car. 

topher800 wrote: Jan 29, 2025 6:45 PM

Etip wrote: Jan 28, 2025 4:00 PM

Hey. Is this a custom or preFab box? If Prefab, who makes it/what model is it? I'm in the process of putting together a stereo for my car. 

It is indeed custom.  I just thought I'd through the pics at the thread.  It was done by Elevated Audio in Denver.

Chris

 

topher800 wrote: Jan 29, 2025 6:45 PM

Etip wrote: Jan 28, 2025 4:00 PM

Hey. Is this a custom or preFab box? If Prefab, who makes it/what model is it? I'm in the process of putting together a stereo for my car. 

It is indeed custom.  I just thought I'd throw the pics at the thread.  It was done by Elevated Audio in Denver.

Chris

alemac1 wrote: Feb 04, 2025 6:21 AM

topher800 wrote: Jan 29, 2025 6:45 PM

It is indeed custom.  I just thought I'd throw the pics at the thread.  It was done by Elevated Audio in Denver.

Chris

Might be a daft question, but I assume that is an 8" ?

topher800 wrote: Feb 06, 2025 4:31 PM

alemac1 wrote: Feb 04, 2025 6:21 AM

Might be a daft question, but I assume that is an 8" ?

It is an 8"

AUDISON PRIMA FOR SEALED 8" SHALLOW DUAL 4 OHM
SUBWOOFER 250W RMS

 

When I had my 02 I used a jl audio 6w3v3 in a custom fiberglass box. It helped fill in the low end. Might be a option if you are not looking for car shaking bass. I use a jl 10tw3 in the e28's trunk and it does not take up to much room at all. I have the amp under the rear seat

I know I'm late to the party but here's my setup. Infinity Basslink I installed behind the passenger seat. It has all the bass I could want in the e28 and then some - don't even have the gain turned up all the way.


 


 


 

 

Are there any pre-fab underseat sub boxes that fit under the back seat? I am hoping to put some bass in without having to have a box made. Appreciate anyone's input that has one.

Thanks.