[rd5150]

For those of you that have an aftermarket sub in the trunk, did you do anything to modify the trunk to help air move to the cabin? This car doesnt have folding rear seats, or the pass through in the arm rest, so it seams pretty tightly sealed.

 

[Mattbuyshouses]

one 4 channel alpine and one 2 channel alpine both putting out some pretty good heat. No changes to the trunk at all, there's a lot of air space back there. Do have the ski pass knocked out and open air to the back with the arm rest down. Have not had a problem with heat at all and I like to listen to my music pretty loud.

 

[rd5150]

I'm not really worried about heat, just sound. I had 2 alpine TYPE R 10s and a JL 500.1 that sounded great in my previous car,, but i could barely hear it in this one. Now I just have a single 10, same amp and I'm sure i won't have any better results than i did before.

 

[Mattbuyshouses]

Ah, I misunderstood when you said help air move to the cabin.

I've got a single 12" Image Dynamics that thumps. Even with the armrest up and "sealed" there's still a ton of low end.

 

[lrinco01]

rd5150, what kind of enclosure do you have the 10" in? sealed will give you tight bass but Ported or Bandpass will Thump with the Right Sub/Amp/Tuned properly

 

[rd5150]

type r's were in a sealed 1 cu. enclosure each.. but i could barely hear them... actually opened the trunk to see if they were even on,, ive had that same setup in previous cars and it sounded great

 

[lrinco01]

sounds like in this 325i you need a Ported enclosure if you want to retain the same equipment.

what options do you have for a port in your rear deck?

us E46 M3s have a huge hole when we remove the HK Sub so it allows the bass from a sub in the trunk to get into the cabin and for some that is not enough so that make enclosures at the rear that use that hole as there port so the sub fires through that cavity.

check yours out and see what your options are
otherwise you may have to change your sub enclosures and frequency

I assume your subs are playing at 80Hz right?

 

[MuddZHP]

Do you have the ski pass thru plate with a scribed outline with small tack welds? If so use a tool to pop this out along with the attached sound proofing material. Even without the fold down armrest the bass will be much louder.

 

[prettyricky]

You HAVE to pop out the plate behind rear seat. It's perforated in a rectangle. Just take a soft mallot or something and pop it out..Will make all the difference in the world.

 

[e.usaf]

i'm worried about the barrier between the trunk and cabin as well. i'm going to be pushing quite a bit of power so i'm curious to how it's going to sound. i wouldn't recommend removing the plate.. that acts as a strut bar basically. i've seen modified rear decks to help air flow. only other thing i've considered is cutting a gap out of the plate where the arm rest is.

 

[04yfz]

i'm worried about the barrier between the trunk and cabin as well. i'm going to be pushing quite a bit of power so i'm curious to how it's going to sound. i wouldn't recommend removing the plate.. that acts as a strut bar basically. i've seen modified rear decks to help air flow. only other thing i've considered is cutting a gap out of the plate where the arm rest is.

The plate theyre talking about is the one behind the arm rest, and it has absolutely no structural significance.

 

[Mattbuyshouses]

+1 on ^^
If this were to provide support, there's no way the perfs would hold up to any amount of stress. Simply hitting it with your fist knocks the plate out.

 

[e.usaf]

interesting. i had assumed it was identical to the one in my last vehicle. i may have to look into doing that then.

 

[Mattbuyshouses]

makes a ton of difference in the bass coming through that ski pass. I originally left it in thinking it'd be more than enough with the 1 12" sub I have back there. When opened up, the air movement through to the cabin is night and day.

 

[TR4G-]

Make your own ski pass without the ski pass

 

[DMK330]

Yea I got 2 12in L7 kickers and with the seats up everything sealed I rattled off the third brake light, the flat piece behind the rear headrests and rear window bounces/jumps violently. And the sun roof rattles hard but with the sun roof tilted and the rear seats down it's fine depending on the song u throw on lol. But also I'm in a 330ci I didn't pay much attention too see what your in

 

[radarcontact]

You don't need a "port" into the cabin. You know how you can hear the guy's bass from the car next to you? There's no "port" between the two vehicles! Lol
You will hear, and feel, it. No problem!

 

[TR4G-]

You don't need a "port" into the cabin. You know how you can hear the guy's bass from the car next to you? There's no "port" between the two vehicles! Lol
You will hear, and feel, it. No problem!

Our BMWs were designed to dampen the sound from the trunk. It will affect the sub. If you create a port you can have a much better and louder sound at a lower level.

 

[radarcontact]

...and louder sound at a lower level.

Maybe true, I won't say that it's not. However, I have single IDQ12 in a custom fiberglass box, powered by ~350 Alpine watts. It's very loud and sounds fantastic. In the past, I have had the ski pass removed (in fact, I've actually had the whole back seat out for spring cleaning) and I couldn't tell.

EDIT: But then again, my system is engineered for sound quality, not SPL. If you are moving a sh#tload of air, then I guess that's a different story.

 

[aar0n_91]

fold your rear seats down. thats what i do. whole body shakes when they're down. when they're up, you can still feel the bass, but its 60% compared to with the seats down.

if you don't have folding seats, get a coupe =)