Infinite baffle

Rob09msport

Major
Oct 28, 2017
1,929
664
0
Monroe CT
Ride
09 335i msport le mans 18 x5
So I figured while I was waiting on getting my fuel pump kit I would work on my sub install I have took a kappa perfect and mounted it to 3 quarter plywood and put it up against back seats. My only thing is I'm nervous about how to mount it do I just screw it to the back of my seats or what? Right now i have two temp brackets i bent up real quick and drilled small sheet metal screws next to shock towers cause I'm scared to poke holes in diff spots or mess with anything .these pics are without the matchup 7 mounted but just to give idea I plan on either getting carpet or doing vinyl on back and on front putting CF vinyl around sub. It sounds great but at high volume starts losing power but if I wedge board across trunk it pounds so I know I need to figure out mounting and dynamite deck lid and the seam around edge of wood .
 

Attachments

  • 20191028_075307.jpg
    20191028_075307.jpg
    194.7 KB · Views: 148
  • 20191028_075324.jpg
    20191028_075324.jpg
    193.1 KB · Views: 128

Torgus

Brigadier General
Nov 6, 2016
2,671
2,193
0
Boston
Ride
ACF 6466 E92 + METH
Wouldn't a IB in the rear deck be easier? Let the seats seal it up. Should look cleaner too and you still get to use your ski pass and or the split seats etc.
 

Rob09msport

Major
Oct 28, 2017
1,929
664
0
Monroe CT
Ride
09 335i msport le mans 18 x5
You think a 12 would fit their ? And acoustically I have been reading that firing through the seat is better and my car has switched to daily capable toy so idc about fold down. And as embarrassing as this is I didn't know I had fold down seats until I started this
 
Oct 24, 2016
1,152
1,202
0
45
Scottsdale, AZ
The backs of the BMW seats are Sheetmetal, so you can fasten directly to them. I have a 15" IB in my E90, back of seats is what you want to do with heavier/larger drivers. I drilled some "locating holes" that were larger diameter (~3" IIRC) then smaller sized holes near them, used bolts with large washers, put rubber on for some compression/vib absoption and fished the bolts/washers through the seats so the threads protruded out and through my IB board. Reason was I didn't want sharp points poking into the seats. I think I used 1/2" bolts.


IMG_2596.JPG


IMG_2471.JPG


IMG_2625.JPG


IMG_2714.JPG



I'm not sure one 12" driver will do it for you, I'd do at least 2 12's, but if you don't listen very loud or don't have the bottom end equalized you might be ok.

I ended up wrapping it in alcantara. Looks decent.
 
Last edited:

Rob09msport

Major
Oct 28, 2017
1,929
664
0
Monroe CT
Ride
09 335i msport le mans 18 x5
Is that a ib3 ? And I was thinking if spacing it back like you did and I also don't want sharp screws sticking in plus I like the idea of bolts. How did you fish through and I dont want a just bass system so the infinity with the 600 rms gladen putting prob 300 watts caruse free air should be plenty. If I need more I could go with a I'd max or ib3 . I originally wanted a 10 but the infinity runs to 23 hz so I have butterworth set at 42 db and 26 hz I may drop to 24 hz if I feel the suspension can take it and if it pops I'll get a I'd max. I only running to 80 hz and I may go 60 hz with 12db lp instead of the 80 hz at 18 db. I'm having hard time figuring out delay for sub right now I have 13 ms on underseats so it fires rear sub 13 ms ahead but I dont know how much latency gets introduced by the gladen amp and or how much latency from my helix line out "I assume same as pre amp" to its speaker outs
 
Oct 24, 2016
1,152
1,202
0
45
Scottsdale, AZ
It's a Partsexpress Ultimax UM15:


Decent enough, although I have melted one before when listening "spiritedly" with windows down at highway speeds.

Low bass is about displacement, have to move a lot of air, fortunately a car environment is MUCH easier to get loud low bass.

Fishing the bolt/washer/rubber combo through was a giant pain in the ass. I could do it again making less of a mess. The way I did the whole thing is:

1: Laid both seats down flat.
2: Covered entire rear seat area with painter's tape.
3: Put seats back up.
4: Crawl in trunk, using black magic marker trace outline of seatbacks in trunk.
5: Lay seats down flat.
6: Remove, in one piece, painter's tape transfer of baffle shape.
7: Put painters tape on sheet of plywood.
8: Cut out with jig/circular saw.
9: Position baffle on seats in correct location.
10: Choose few key locations for fasteners/mark on wooden baffle.
11: Drill locating holes through baffle and through seat back.
12: Figure out how to fasten to the seat.

This is the pain in the ass part. As you can see in one of my pics, I cut a slot that was good sized enough that I could get my fingers in there, and using various tools and string, basically pushed AND pulled the fastener over to the hole through the main slot, and used my fingers to align the fastener to hole/compress the seat padding enough to get it oriented right. Patience will help you. There are probably better ways to do it, but I didn't want to have anything poking into the seat back and didn't like the traditional wall anchor fasteners. Once you bolt it up, you may have to double-nut the top of the bolt to stop it from spinning while you torque the actual nut down to hold the baffle in place (or you could use vice grips if you're a savage).

You do need to listen with the arm rest down, otherwise you get turbulence sounds from the ski-pass. I also recommend a steep and lower crossover to stop too much upper bass from dominating.
 

Rob09msport

Major
Oct 28, 2017
1,929
664
0
Monroe CT
Ride
09 335i msport le mans 18 x5
[/URL]
These are great if you want little more thump without breaking bank but I also think two 10 inch l7s would move alot of air and fit the ski pass nice.
On my 550 I would be able to do the deck but I dont think their is enough room to do anything except 8s on the deck which ino wouldn't cut it. I'm wondering if would be worth it to pay someone to weld on some studs for mounting or maybe do rivet threads.
 

NoQuarter

Major
Nov 24, 2017
1,662
1,066
0
Indiana, USA
Ride
Z4 35is, 535xi, X5 35i
Removing the leather seat cover and foam seems easier than what you described trying to get the bolt through the hole.

I have done front seats a couple times and the rear once.
 

doublespaces

Administrator
Oct 18, 2016
9,303
4,331
0
AZ
Ride
2009 E93 335i
Yep. I'll take some measurements later, but I have to contend with the roof being down. I think that eats up quite a bit of space.
 

Torgus

Brigadier General
Nov 6, 2016
2,671
2,193
0
Boston
Ride
ACF 6466 E92 + METH
RE XXX 18'' or Sundown team 18'' should fit nice. Get you that SPL you have been missing in your life.

There is nothing wrong with 8 or 10 inch woofers mind you. At the end of the day it's cone area, xmax, and motor force. I'm going to throw four 8s on my boat next season and they will have the same cone area as a single 15.
 

GreyNBlueE92

Sergeant
Oct 3, 2018
266
92
0
27
OH
Ride
2007 E92 335i
RE XXX 18'' or Sundown team 18'' should fit nice. Get you that SPL you have been missing in your life.

There is nothing wrong with 8 or 10 inch woofers mind you. At the end of the day it's cone area, xmax, and motor force. I'm going to throw four 8s on my boat next season and they will have the same cone area as a single 15.

Dont forget box size... Space makes bass!
 

KevinC39

Corporal
Jun 27, 2017
234
118
0
Ride
335i
Wow, you guys really love bass. I've got a single 10 and it's way more than I need. This is a sealed box in the trunk with no fold down seats too. Pretty fun looking set ups in here though.
 
  • Funny
Reactions: GreyNBlueE92
Oct 24, 2016
1,152
1,202
0
45
Scottsdale, AZ
So, do you think I could fit something interesting in here?

View attachment 32791


Something with one or two tang band 1139's.


Try to port it to 34hz or so, you'll want some DSP for signal shaping, but they're more than sufficient for some good tunes. I have a couple in my focus and they'll hit 118+ dB peaks, which is loud enough for the average person. Very impressive 6.5's, cheap, and don't need much power. IIRC I'm giving mine ~100 watts from a bargain basement amp. (hey, it's a commuter car!)
 
  • Like
Reactions: doublespaces
Oct 24, 2016
1,152
1,202
0
45
Scottsdale, AZ
RE XXX 18'' or Sundown team 18'' should fit nice. Get you that SPL you have been missing in your life.

There is nothing wrong with 8 or 10 inch woofers mind you. At the end of the day it's cone area, xmax, and motor force. I'm going to throw four 8s on my boat next season and they will have the same cone area as a single 15.


I don't think you could fit an 18 on that rear seat -maybe if you installed it with the seat closed (have fun), my 15 is pretty close.

And yes, with DSP cone size doesn't matter as much any more, as long as the drivers are located close enough to couple as one (in a car, with low freq's, they do). Just remember making a driver excurt further is the least efficient means of getting more bass. it's what most sane people do though (vs. my "few dozen 12's but who is counting" home projects)

Wow, you guys really love bass. I've got a single 10 and it's way more than I need. This is a sealed box in the trunk with no fold down seats too. Pretty fun looking set ups in here though.

If you target a rising low end response, and want things to go pretty deep, you will run out of capability quick. These cars aren't a true IB, sort of cross between open baffle and lossy big sealed, meaning they have a lot of low end cancellation, so doing it like I have (and Rob is), you'll tend to need a little more ooomph to reach normal levels. A sealed box in trunk with same driver would be louder, never mind a ported or bandpass.
 

Rob09msport

Major
Oct 28, 2017
1,929
664
0
Monroe CT
Ride
09 335i msport le mans 18 x5
I wish I had e93 for this alone
 

Rob09msport

Major
Oct 28, 2017
1,929
664
0
Monroe CT
Ride
09 335i msport le mans 18 x5
I hope someone isnt screwing people cause I just bought something from forum member and I sent the money and was supposed to send me tracking last Monday.