Install Larger 8" Sub Upside Down in Underseat Enclosure?

Camman · 12-02-2016, 01:04 PM

So I have an E90 (HiFi system) without the rear folding seats and that means that a trunk sub is almost useless because the seat and back panel will rob much of the sound. Upgrading to folding seats is not really worth it at this point.

I've been doing some research regarding upgrading the underseat subs and it seems that the enclosure for the OEM 8" subs is quite small so the options to upgrade are limited. What I'm wondering is, if I got a larger 8" sub, could I mount it upside down in the enclosure? I know I wouldn't be able to install the grill back on but it would be under the seat so no one would see anyways. If it is possible, this would give a little more enclosure space for the sub thus a little bit better of a sound overall, no?

Just curious if anyone has explored this option and what y'alls thoughts are on this?

Edit: I know a shallow mount sub would still be required because there's still not much space between the floor and the bottom of the seat.

banshee28 · 12-02-2016, 09:35 PM

I have not done that, but I have upgraded my underseats to 10" Morels. It will take a little Dremel work to modify the enclosure but they will sound great!

3002 tii · 12-08-2016, 11:59 PM

Don't have the answer but why would folding seats make that much of a difference for a trunk sub? Once the the seat backs are upright isn't it all the same?

Bmans08 · 12-09-2016, 07:24 AM

I just put two JL 12w3 in the trunk . Makes a huge difference . Low frequency carries . You won't get air movement but you will get the sound .

ctuna · 12-09-2016, 02:03 PM

The Hi Fi amp is the biggest problem in the Hi Fi system however
the speakers are not that good either. You will get some actual
bass out of the under seats if you add a better amp and and amp
will make the rest of the system much better to. Most people will
be quite pleased with just upgrading the amp and speakers unless
you like bass to the exclusion of the rest of the frequency range.
The bass out of the underseats is quite muddy with an amp only
solution. I have to think that adding a sub only will overwelm the
rest of the system though.

WickedE93 · 12-13-2016, 01:50 AM

Quote:

Originally Posted by banshee28

I have not done that, but I have upgraded my underseats to 10" Morels. It will take a little Dremel work to modify the enclosure but they will sound great!

Pics and diy?!

bacon33 · 12-22-2016, 01:32 AM

Ctuna i agree the under seat speakers sound good once the right amp is hooked up. Unless you are looking at crazy bass. Upgrading door speakers and amp made a huge difference.

Camman · 12-22-2016, 04:04 PM

Quote:

Originally Posted by ctuna

The Hi Fi amp is the biggest problem in the Hi Fi system however
the speakers are not that good either. You will get some actual
bass out of the under seats if you add a better amp and and amp
will make the rest of the system much better to. Most people will
be quite pleased with just upgrading the amp and speakers unless
you like bass to the exclusion of the rest of the frequency range.
The bass out of the underseats is quite muddy with an amp only
solution. I have to think that adding a sub only will overwelm the
rest of the system though.

Can the stock speakers handle an upgraded amp?

ctuna · 12-23-2016, 11:32 PM

The common amp to put in a Hi Fi was a Jl 600/6
Technic use to do this all the time and though it ends
up being 100 watts per channel due to the 2 ohm speakers
if you don't slam it people have not reported smoke .
I ran my Jl for a few days on the stock speakers and it
improves the sound quite a bit but the underseat bass is
kind of muddy but there is actually bass where there wasn't
any before.
A set of one of the common three way speaker kits mentioned
in the speaker list in the audio build thread will make a big difference.
The Helix 82 dsp would be running at 70 watt per channel on the stock speakers.
same speakers and Bimmertech sells that as no other speakers necessary
setup though they do support some aftermarket setups with tunes for
the dsp.

12-02-2016, 01:04 PM	#1
Camman What am I doing here? 190 Rep 463 Posts Drives: 07 328i 6MT Join Date: Sep 2013 Location: Houston iTrader: (0)	Install Larger 8" Sub Upside Down in Underseat Enclosure? So I have an E90 (HiFi system) without the rear folding seats and that means that a trunk sub is almost useless because the seat and back panel will rob much of the sound. Upgrading to folding seats is not really worth it at this point. I've been doing some research regarding upgrading the underseat subs and it seems that the enclosure for the OEM 8" subs is quite small so the options to upgrade are limited. What I'm wondering is, if I got a larger 8" sub, could I mount it upside down in the enclosure? I know I wouldn't be able to install the grill back on but it would be under the seat so no one would see anyways. If it is possible, this would give a little more enclosure space for the sub thus a little bit better of a sound overall, no? Just curious if anyone has explored this option and what y'alls thoughts are on this? Edit: I know a shallow mount sub would still be required because there's still not much space between the floor and the bottom of the seat. __________________ N52 : 6MT : ZSP : ZPP : BC Racing Coilovers : BMW PE
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12-02-2016, 09:35 PM	#2
banshee28 Private 3 Rep 72 Posts Drives: 2006 330i 6MT ZSP Join Date: Feb 2011 Location: FL iTrader: (1)	I have not done that, but I have upgraded my underseats to 10" Morels. It will take a little Dremel work to modify the enclosure but they will sound great!
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12-08-2016, 11:59 PM	#3
3002 tii Lieutenant General 2286 Rep 12,565 Posts Drives: Z4 M, X5, GX460 Join Date: Apr 2008 Location: CT iTrader: (99) Garage List F15 X5 xDrive35i [8.75] E86 Z4 M [10.00] F10 550i (Retired) [9.17] F25 X3 xDrive35i (R ... [9.43] E82 135is (Retired) [9.50] E85 Z4 M (Retired) [9.41] E90 328i xDrive (Re ... [9.25] E86 Z4 3.0si (Retired) [9.24]	Don't have the answer but why would folding seats make that much of a difference for a trunk sub? Once the the seat backs are upright isn't it all the same? __________________ Follow for latest mods
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12-09-2016, 07:24 AM	#4
Bmans08 Bman's 328 0 Rep 25 Posts Drives: Black 08 328i Join Date: Oct 2016 Location: Tennessee iTrader: (0)	I just put two JL 12w3 in the trunk . Makes a huge difference . Low frequency carries . You won't get air movement but you will get the sound .
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12-09-2016, 02:03 PM	#5
ctuna Lieutenant General 1911 Rep 13,104 Posts Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca iTrader: (0)	The Hi Fi amp is the biggest problem in the Hi Fi system however the speakers are not that good either. You will get some actual bass out of the under seats if you add a better amp and and amp will make the rest of the system much better to. Most people will be quite pleased with just upgrading the amp and speakers unless you like bass to the exclusion of the rest of the frequency range. The bass out of the underseats is quite muddy with an amp only solution. I have to think that adding a sub only will overwelm the rest of the system though.
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12-22-2016, 01:32 AM	#7
bacon33 Private 9 Rep 75 Posts Drives: 335i Join Date: Mar 2013 Location: San Diego iTrader: (0) Garage List 2012 BMW 335i Dinan 3 [0.00]	Ctuna i agree the under seat speakers sound good once the right amp is hooked up. Unless you are looking at crazy bass. Upgrading door speakers and amp made a huge difference.
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12-23-2016, 11:32 PM	#9
ctuna Lieutenant General 1911 Rep 13,104 Posts Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca iTrader: (0)	The common amp to put in a Hi Fi was a Jl 600/6 Technic use to do this all the time and though it ends up being 100 watts per channel due to the 2 ohm speakers if you don't slam it people have not reported smoke . I ran my Jl for a few days on the stock speakers and it improves the sound quite a bit but the underseat bass is kind of muddy but there is actually bass where there wasn't any before. A set of one of the common three way speaker kits mentioned in the speaker list in the audio build thread will make a big difference. The Helix 82 dsp would be running at 70 watt per channel on the stock speakers. same speakers and Bimmertech sells that as no other speakers necessary setup though they do support some aftermarket setups with tunes for the dsp.
	Appreciate 0 Quote