# Stereo Integrity BM mkIII Subwoofer



## mSaLL150 (Aug 14, 2008)

This is the first review I've written on the board so take it with a grain of salt.

I bought a pair of BMs for the pre-order as I had been anticipating these for what feels like years. Under the back seat of my truck has very limited space which calls for a shallow subwoofer that needs minimal airspace. I've had 3-4 different substage setups in the truck before today, all consisting of 1 or 2 shallow 10" subwoofers.

I finally had some free time the past couple days to build a box and get these subs in my truck (2 BMs). They are in a 50" long by 4.2" tall box under the rear seat in a downfiring configuration, split chambers at .46 cubic ft per sub stuffed with polyfill. Although I was stoked about the specs of the BM, I've always been a little skeptical of their actually performance. Even today putting them in the box, I was thinking to myself "no way are these going to play down into the lowest octaves in a box this tiny..."

I was very wrong. After setting the gain on my Cadence iA7 and setting the crossover point, I took about an hour and a half listening session with the BMs. I previously was using a pair of Adire Koda 10" subwoofers which actually seem to share a lot of common parts with the BM (XBL^2 motor, surround material, spider material, same rubber gasket, woven tinsel leads etc). I was completely satisfied with the Kodas, but I must say that everything the Kodas did well the BMs do better. 

I listened to a few of my reference discs, and immediately was blown away. The BMs blend right into the sound stage, impossible to localize until high volume when the seats in my truck start shaking. Blending them to my Seas w18nx midwoofers was extremely easy and they are a great combo. Listening to the Eagles Hell Freezes Over album was pretty awesome. The BMs do an excellent job distinguishing between the bass guitar and kickdrums, never missing a beat and no muddiness.

Next I listened to some harder rock, and ended up listening to Seether - "Fake It" twice. The first time was at a moderate listening level, and again the bass was right up front, kickdrums were very tight and the bass notes during the chorus were played with authority and clarity. The second time I listened to this song I turned it up quite loud and opened up the gain on the amp a bit (I have the gain knob under the steering wheel for easy access). Man, this gave me a big smile and a little chuckle. The BMs are loud. VERY loud. I was simply stunned at the output these shallow subs have in such little airspace. Even at very high volume, the BMs remained composed and under control...no distortion. Rob Dougan's "Clubbed to Death" off the matrix soundtrack has some really subsonic material and the BMs crank it out without a hiccup. They can play LOW.

Just for fun I listened to a couple Young Jeezy songs, and simply put...they put out way more bass than anyone should ever need. Even when the subs are barely moving, it really amazed me the amount of sound they produced (cabin gain really does seem to help the BM). Unless you saw them you would never imagine their shallowness or the enclosure size...they sound everything like a normal sized woofer in a normal sized box.

I do have a few gripes about the BM. First and foremost is the mounting gasket. What a PITA to screw them in with this thing. It does look nice when finally mounted though, but I can see how it can be accident prone (I know some people have punctured their BM because of this difficulty). The Kodas have the exact same gasket but with holes in the front which makes it much easier to mount them. I also wish the holes in the BM's terminals were slightly larger. My stinger 12awg _barely_ fit into them. 

Also one of my BMs has some mechanical noise at moderate to high volume. Sounds like something may be loose inside the driver or maybe a wire in the box is hitting the underside of the cone...I need to pull it out and investigate.

A lot of my friends have trucks with underseat setups similar to mine with shallow subwoofers (Rockfords, Pioneers, Kenwoods, JLs etc). None of these shallow drivers come close to the BM in both clarity and output. I've had seat time with the SI Mag v4, DIYMA r12, Morel Ultimo, IDQv2 and I wouldn't hesitate to compare the BM up against any of them. This subwoofer is a real winner for anyone with tight space constraints, congratulations to Nick for an amazing product. 

_*I will update when I've had even more time with the BMs and they have broken in a little more (and hopefully solved the mechanical noise issue). _


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## RattyMcClelland (Nov 28, 2008)

Excellent review.
And they have not even been run it yet. Keep an eye out on this.


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## Electrodynamic (Nov 27, 2007)

Nice review, very thourogh and well written  Let me know if the noise turns out to be the actual driver and not a wire and I'll take care of it for you.


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## ItalynStylion (May 3, 2008)

Glad to see that other people are enjoying them too! I've lead a bunch of the IS300 guys down the SI BM path with the stealth enclosure I build for the Lexus. All of them really seem to enjoy the sub as well.

I feel ya on the mounting gasket. It's great but it's not without it's own stubborn nature.


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## 6262ms3 (Feb 27, 2008)

Nice review, I'm hoping to put mine in this weekend, gettin' excited!


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## Boostedrex (Apr 4, 2007)

Marc, are you coming to the Santa Rosa MECA show on April 3rd? I'd really like to hear your truck now that it's changed so much from last time I saw it. Come on out and put that thing in the lanes! 

Very nice review by the way. And I agree about Nick having a winner on his hands with these subs! Mine will be in this weekend and I can't wait.

Zach


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## mSaLL150 (Aug 14, 2008)

Boostedrex said:


> Marc, are you coming to the Santa Rosa MECA show on April 3rd? I'd really like to hear your truck now that it's changed so much from last time I saw it. Come on out and put that thing in the lanes!


I may try to make it out to hang out and get some advice. But the truck has a way to go before it enters any lanes. I need to really clean up the install, deaden the crap out of the floor because you can feel the vibrations through the seats too much, and get the tweeters molded up into the pillars (my stage has the rainbow effect with the tweets in the doors).


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## snaimpally (Mar 5, 2008)

Nice review. Hope to see some more reviews.


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## Boostedrex (Apr 4, 2007)

I'll be writing up a new review in the next several days. Seeing as my first review was for a single MKII prototype vs the pair of MKIII production models I now have, I feel it's a good idea.


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## rockinridgeline (Feb 2, 2009)

I have a single BM under the seat in my Ridgeline. Ditto what was already written about the outstanding ability of these subs to blend with the front stage. Running mine off of a Zapco DC500.1. The BM blends better than the DIYMAR12 that I had ran previously. Kick drums are right up front, along with the bass guitar. Even thought I have ran my Dyn MW182's down to 45 Hz previously, I am not running them at 80 Hz, taking the stress off of them at high volumes. Everyone that has listened to my setup says they can not locate the sub at all.

This sub is a real winner and a bargain. When you consider the tight spaces it will fit in, it is an absolute home run for car audio!


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