# BMW Underseat Midbass Fun



## jamesjones (Mar 8, 2007)

I'm in the middle of purchasing a 2013 BMW X5 xdrive35d and I'm already making plans to upgrade the audio. I saw another user here was able to squeeze a Morel HCW10 under his e90 I thought I'd take a stab at squeezing some Illusion Carbon 10s in mine. Since I don't have my vehicle yet I ordered a e70 underseat speaker from ebay so I could do some experimentation. Unfortunately it looks like they won't fit at all or will take some serious modification.

Here's the C10 compared to the housing...


















Here's the depth of the housing compared to the C10...










Here's the major issue fitting the woofer into the housing...










The wide basket make notching of the the enclosure a requirement which would open up holes in the housing. I could possibly notch it and use it as a mold to build a fiberglass housing.

This is what makes me think it could be possible to make it work...










The height of the surround is pretty close to exactly the same height as the mounting surface for the stock grills. A possible issue is the magnet and where it lines up in relation to the seat rail. Without having the vehicle in hand to measure I can't say for sure. Looking at pictures on line it looks like it will be close.

Here's the C10 next to the stocker...


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## jamesjones (Mar 8, 2007)

Here's a Kicker SSMB8 that I bought from another user here that fits pretty much without issue so it's pretty safe to say an Illusion Carbon 8 would fit...


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## theobjectivist (Sep 29, 2016)

Are you certain squeezing such a large driver into tiny space will work? What about going smaller and making the most of the volume? 

e.g - a high excursion 6.5" or something


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## robtr8 (Dec 6, 2011)

On the recommendation of Musicar NW, I did the Jehnerts. I did the Morel Primo at the same time and while the bass was way better, I can't say that the midbass was much better at all. Then I installed the GB40's. Phenomenal.


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## jamesjones (Mar 8, 2007)

theobjectivist said:


> Are you certain squeezing such a large driver into tiny space will work? What about going smaller and making the most of the volume?
> 
> e.g - a high excursion 6.5" or something


It's not a closed enclosure. It has a vent that vents into the frame I believe so it's somewhat IBish.


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## jamesjones (Mar 8, 2007)

robtr8 said:


> On the recommendation of Musicar NW, I did the Jehnerts. I did the Morel Primo at the same time and while the bass was way better, I can't say that the midbass was much better at all. Then I installed the GB40's. Phenomenal.


Yeah, I know the Jehnerts are what the BMW guys recommend but I wanted to try using a shallow midbass that is more commonly used in quality systems here in the US.


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## banshee28 (Mar 23, 2006)

jamesjones said:


> I saw another user here was able to squeeze a Morel HCW10 under his e90 I thought I'd take a stab at squeezing some Illusion Carbon 10s in mine.


 So.....I now have those same 10's under my seats in my E90. First let me say that you CAN make them fit, but it will be LOTS of Dremel work cutting the plastic, checking fitment, and cutting again. From what I understand it will take a WHILE. Thanks Kai for doing all the hard work for these! 

Another option to allow them to vent properly, is to simply cut a hole in the sheet-metal under the sub area, using a 3" hole-saw or something. This way the air vents under the car similar to IB. :laugh:

Now as far as how they sound.... Personally, I am trying to follow a typical SQ house curve, currently using Jazzi's, so all my speakers have to pretty much be in alignment with that, not more not less. I have them crossed around 60Hz or so to a little over 200Hz. 

How do they sound? ................ Midbass is awesome, up front, and even the lower bass notes are perfect, as now they perfectly blend into my Sub which plays 60Hz and lower....

So I would say if you have time, try to get the Morel or even the other 10's to fit. They may not be a huge difference over 8's, but they easily play in this range and sound really good doing it! I am very happy with my 10's.


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## Jscoyne2 (Oct 29, 2014)

Idk how the baffle fits but would it be possible to ditch the plastic and make it out of wood

Sent from my SGH-M919 using Tapatalk


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## jamesjones (Mar 8, 2007)

Jscoyne2 said:


> Idk how the baffle fits but would it be possible to ditch the plastic and make it out of wood
> 
> Sent from my SGH-M919 using Tapatalk


I won't know for certain until I get in there but here are some pictures from am install that MusicarNW did in an E70...




























It looks like there is some room under there to build something. The issue is that the seat rail goes over that space so I don't know if there's space to be gained by building my own enclosure out of wood.

Hacking and patch or hacking and making a mold seems like the best bet if I want to try and use the C10.


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## jamesjones (Mar 8, 2007)

banshee28 said:


> So.....I now have those same 10's under my seats in my E90. First let me say that you CAN make them fit, but it will be LOTS of Dremel work cutting the plastic, checking fitment, and cutting again. From what I understand it will take a WHILE. Thanks Kai for doing all the hard work for these!
> 
> Another option to allow them to vent properly, is to simply cut a hole in the sheet-metal under the sub area, using a 3" hole-saw or something. This way the air vents under the car similar to IB. :laugh:
> 
> ...


Those HCW10s are almost impossible to find nowadays.


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## banshee28 (Mar 23, 2006)

jamesjones said:


> Those HCW10s are almost impossible to find nowadays.


Yes! I think I may have purchased the very last ones available a while back. IF anyone is interested in these, send me a PM, I may have a set available soon!


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## jamesjones (Mar 8, 2007)

Well, I ordered some 10" rings to see if there is anyway to use them to modify the current enclosure to make these work...not happening.

Time to order some knytex and solarez. I'm going to attempt to build a housing with fiberglass that mimics the stock housing just slightly larger.


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## brainbot1 (Feb 19, 2016)

Subbed, just got an 09 328xi coupe, need to figure out how to upgrade the underseat woofers without getting ripped off by all the Bimmer-centric companies. Ported figerglassed 8's came to mind. Peerless SLS seems like a wise choice but if you got those C10s in there it would be ****ing awesome.


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## jamesjones (Mar 8, 2007)

brainbot1 said:


> Subbed, just got an 09 328xi coupe, need to figure out how to upgrade the underseat woofers without getting ripped off by all the Bimmer-centric companies. Ported figerglassed 8's came to mind. Peerless SLS seems like a wise choice but if you got those C10s in there it would be ****ing awesome.


I decided to throw in the towel. I found a buyer for my C10s. I'm probably just going to keep searching for a set of C8s and call it a day.


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## brainbot1 (Feb 19, 2016)

jamesjones said:


> I decided to throw in the towel. I found a buyer for my C10s. I'm probably just going to keep searching for a set of C8s and call it a day.


How many cubic feet or liters do you think you have in yours? Are you still planning on making a fiberglass enclosure? I will definitely be looking to do this once spring hits. I pulled the seats last weekend, seems like I have a fair amount of space under my seats to substitute a large woofer. Ill be shooting for 10's.


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## jamesjones (Mar 8, 2007)

I can't catch a break with this thing. I got a hold of a set of Audio Development w800neos, which look like some pretty stout drivers that are super thin...




























other than the ginormous bolt for the leads...










What good does it do to build a super shallow speaker that has a giant lead that won't let you take advantage of the shallow depth?

Are leads pretty easy to change?


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## Onyx1136 (Mar 15, 2009)

Those look to be pretty simple to change out.


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## jamesjones (Mar 8, 2007)

Onyx1136 said:


> Those look to be pretty simple to change out.


Yeah, I think I just need to separate the lead from the bolt and then install some new binding posts and solder the lead to the the new one.


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## TommyDS (May 27, 2012)

Having an E93 2011, I have found the German Maestro SWF8012HE Maestro Car Audio - subwoofer that has also adapter ring for BMW. Thinking about buying them, cause Illusion Audio is not available in Europe, and this GM looks comparable to them.


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## jamesjones (Mar 8, 2007)

TommyDS said:


> Having an E93 2011, I have found the German Maestro SWF8012HE Maestro Car Audio - subwoofer that has also adapter ring for BMW. Thinking about buying them, cause Illusion Audio is not available in Europe, and this GM looks comparable to them.


Those look pretty sweet and do look like Illusion clones. I wouldn't be surprised if they're from the same build house in India.


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## rton20s (Feb 14, 2011)

They have an inverted motor, but I doubt there is much else in common with the Illusion design. Probably not even the same build house. I thought German Maestro had their own build facilities?


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## TommyDS (May 27, 2012)

rton20s said:


> They have an inverted motor, but I doubt there is much else in common with the Illusion design. Probably not even the same build house. I thought German Maestro had their own build facilities?



Yes, different basket & should be Made in Germany. At least they make many of their higher end products in-house in Germany


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## brainbot1 (Feb 19, 2016)

do you think you have 2.5 inches of mounting depth? The slim peerless 10 seems like it would be a great choice. Do you think it would react like a sealed woofer in a small enclosure or more IB? I pulled my seats out but couldn't really tell what was going on under the carpet. Need another weekend to investigate. 

https://www.madisoundspeakerstore.com/approx-10-woofers/peerless-gbs-250f38cp01-04-10-slim-woofer/


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## jamesjones (Mar 8, 2007)

brainbot1 said:


> do you think you have 2.5 inches of mounting depth? The slim peerless 10 seems like it would be a great choice. Do you think it would react like a sealed woofer in a small enclosure or more IB? I pulled my seats out but couldn't really tell what was going on under the carpet. Need another weekend to investigate.
> 
> https://www.madisoundspeakerstore.com/approx-10-woofers/peerless-gbs-250f38cp01-04-10-slim-woofer/


I have the depth but I just don't think I have the room under the seat for a 10" speaker. It's going to be right with these 8s.

I believe the e9x cars have slightly more room though. I have seen pics of the Morel HCW 10 installed in an e90 so in that car it's possible at least.


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## TommyDS (May 27, 2012)

brainbot1 said:


> do you think you have 2.5 inches of mounting depth? The slim peerless 10 seems like it would be a great choice. Do you think it would react like a sealed woofer in a small enclosure or more IB? I pulled my seats out but couldn't really tell what was going on under the carpet. Need another weekend to investigate.
> 
> https://www.madisoundspeakerstore.com/approx-10-woofers/peerless-gbs-250f38cp01-04-10-slim-woofer/


Not yet available, but 8inch version of Peerless GBS under construction https://www.tymphany.com/peerless/driver-search-results/driver-detail/?id=1229


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## sheltonlp (Dec 7, 2011)

Why not just use one of the multiple direct swap speakers made by Bavsound, Bimmertech, RF, etc, etc?


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## diy.phil (May 23, 2011)

that's ok... many different speakers and different ways to put something in there.


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## JimmyDee (Mar 8, 2014)

I'm in the same boat as the OP... 
A couple weeks ago, I traded-in my Audi for a new BMW 440i.

You need to decide what you want to use that space for... sub or midbass?
In order to get a full sound stage up front, I decided to abandon the underseat sub idea.
I just replaced the stock underseat speakers with Jehnert (direct swap) speakers.
I'll tune the Jehnert's to play from 80Hz to about 250Hz, then mount a proper sub in the trunk.

I've got Scanspeak 12M's for the doors, with Sinfoni tweeters.


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## TommyDS (May 27, 2012)

Changed my mind, and have found the new Morel Slim series MSW 265 https://www.parts-express.com/morel...8-composite-paper-cone-woofer-4-ohms--297-008 (as the full front will be from Morel) 
Not yet on stock, but in few weeks should be available, according to the European distributor...


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## Stereowhore (Aug 29, 2015)

i use morel admw9 with some spacer rings. fit good. sound great.


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## brainbot1 (Feb 19, 2016)

I went with the earthquake SWSs at 2 ohm. They have a surprisingly amount of Xmax (23mm one way??). I have them crossed at 40hz and giving them 175 watts, they get too loud for comfort but have minimal distortion. Sold buy and install was a breeze. I just recommend you solder directly to the speaker and not use the push terminals that come with them since they are cheap and leaky air. I am not sure if the enclosure is sealed or not. It seems like it goes into the frame of the door and I couldnt find if it vented out or not. But plenty of low end. I have them crossed up at 350 hz and they don't pull the sound stage down too much.


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## rton20s (Feb 14, 2011)

brainbot1 said:


> They have a surprisingly amount of Xmax (23mm one way??).


There is no way I believe any of the SWS Xmax claims are accurate. With only a 52mm mounting depth, you might be very lucky if this were a two way number for 70% BL. Or maybe a one way Xmech? Without Klippel data, I will never believe their one-way Xmax figures.


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## brainbot1 (Feb 19, 2016)

rton20s said:


> There is no way I believe any of the SWS Xmax claims are accurate. With only a 52mm mounting depth, you might be very lucky if this were a two way number for 70% BL. Or maybe a one way Xmech? Without Klippel data, I will never believe their one-way Xmax figures.


I absolutely agree, with that said, they do get plenty loud with a 40hz LR2 xo at full volume (ppi 350.2) with no major perceivable distortion. Just had to give it a little EQ in the 150-250 range (room nodes?).

It is interesting having these under the seats, kick drums go right through the floor through my feet. I don't love the feeling but my girl really does and its her car.


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## MylesR (Apr 20, 2016)

Did you end up trying the Morel MSW 265?


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## Stereowhore (Aug 29, 2015)

I use those. They sound great, very accurate. However, I had the 8 ohm version and 4 ohm and admw9's. I've blown one of each with some high spirited listening.... Bridged into Arc Audio ks300/4.


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## coolassloserp (Oct 17, 2011)

Hi,

I’m also looking to upgrade my 2011 BMW 3 series. Currently going through options for under seat dedicated midbass. Understand the Jehnerts will work well as many have used it. 

I’m curious about the Illusion Audio C8s as some of you have ran those under the seat. For the Illusion C8 - won’t they be a bit restrictive due to space? Did you have to make lots of modifications to make them fit and sound good? Any photos or DIY?

Thanks!


Sent from my iPhone using Tapatalk


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## WLorenzo973 (Aug 27, 2019)

I'm also on the same boat trying to figure all this out lol. I have the convertible so a sub in the trunk isn't going to happen. I just wanted a good 3 way set up front but have limited options with the shallow 8's. I really wanted the dynaudio or morel 3 way set up but according to all that I've read, the 8's from those sets will not fit. For my low end bass, I may try to see how I can do one of those 6.5 sundown subs in the rear armrest area.


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## JimmyDee (Mar 8, 2014)

https://www.diymobileaudio.com/foru...l-gallery/421173-w800-neos-bmw-underseat.html

https://www.caraudiojunkies.com/showthread.php?3533-BMW-440i-Build


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## WLorenzo973 (Aug 27, 2019)

jimmydee said:


> I'll have to look at this from another computer other than my office computer because it blocks out the pics lol. I would love to get better options than the earthquakes everyone speaks of.


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## JimmyDee (Mar 8, 2014)

WLorenzo973 said:


> jimmydee said:
> 
> 
> > I'll have to look at this from another computer other than my office computer because it blocks out the pics lol. I would love to get better options than the earthquakes everyone speaks of.
> ...


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## WLorenzo973 (Aug 27, 2019)

jimmydee said:


> WLorenzo973 said:
> 
> 
> > The Earthquakes are nothing special...
> ...


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