MFW-15 Dual Opposed Build

Well I finally got my build completed. I was looking at replacing my THT's and SVS PB12-nsd with some sealed subs. I wanted to try to get to 10hz with some db's.

I was first looking at the Tempest X2's or some AV15H's, after posting some ideas on here I was getting recommendations for the FI drivers, Mach 5's, and the Dayton 390HF's. So I got to modeling, I was starting to like the Daytons for the price (1000$ budget for the drivers) I wanted to build at least 4 cabs so I could spread them around if I needed to.

One day I got on here and I had a PM from coctostan telling me to take a look at the MFW-15 drivers in a dual opposed sealed setup. So I got to modeling them, 8 looked real good in 4 dual opposed cabs at right around 6 cubes each. 6 cubes was a little small and gave me a Q of .82 but it did help control excursion (i have an EP 4000), and I figured I could stuff the cabs to give it a boost in apperent volume.

After I figured out this is what I wanted to try I ordered 10 drivers from Danny at GR research (I only needed 8 but what the heck), shipping took about 4 days to Ohio. Bought me 6 sheets of 3/4 aruaco ply, I should only need 5, but I had to borrow the truck, so I picked up 1 extra sheet (never did need it, I may use it for one of the other drivers).

So I started building:

the outside dimensions for each cab are 23.5 x 23.5 x 26.5, with double baffles, and 2 window braces. I added 6lbs of polyfil to each cab, which should have gave me around a 25% increase in cabinet volume. The build was pretty straight forward and everything went together well, I used PL premium and an air nailer for everything but the baffles which I used regular wood glue and screwed them together and let them dry over night.

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Having trouble posting pics in the reserved spots.

Drivers arrived:

More build Pics:

All most completed:

Yeah I guess it is

They were not double boxed, they probably should have been, Some of the foam gaskets on the front were slid from there normal spots and rubbing the surrounds. But this most likely wasn't from shipping just the way they are packed with only foam on the motor side. I just removed the foam and used a marker to color the paper material black, you cant tell the difference.

Yeah they were 2 boxes taped together.

I use 1/2" roundover on the top and the front(s), I think it looks pretty good. I am thinking of painting them with Duratex, I used the truck bed liner on my THT's, while it looks good, the bed liner is just a little to rough for my tastes.

Now for some measurements:

I have both a DCX and the BFD. I used a LP12db slope filter (10db boost)centered at 20 to boost the low end and used the BFD to EQ and apply the cuts needed to bring the 80hz end back down to reasonable levels. I watched WOTW with it at my normal listening volume and didn't hear any crazy sounds from the drivers. Here is my current EQ'd graph, no smoothing at listening position.

Edit: I messed up on my rew graph, forgot to reload my ecm8000 calibration file........
I will post a new graph tomorrow, the good thing is I shouldn't need to boost as much, embarrassing.........

WMD, I am only using 1 ep4000, during wotw I hit 120 a couple times. I am eqing out a couple of 10db peaks at 40 and 70 hz, I had the same modes with my other subs also. I havent pushed them to their limit yet, dont want to bust anything yet.

Erich,
They are one heck of a deal, I cant wait to see what lilmike comes up with he is a hornresp master. I do have 2 drivers left over.......

Thanks, the thts are great also, I really just wanted to try to get lower. More or less the low cost drivers gave me an avenue to try it out and it worked!

I was going to go with MDF at first, glad I didnt the dust from the plywood was bad enough.


I can assure you there is another woofer back there, hard to take pictures of both sides ar once

Thanks Coctostan, you are the one that turned me on to these and I am glad you did. As for THD measurements ask and you shall receive.

I have also attached a correct REW graph. I am only using 3db of boost on the low end to get these measurements.


The MFW-15s are only rated for 225 watts so one EP 4000 will and do power 8 easily