This is my first sub build. I’ll be using the Martycube design, and the cabinet will be approximately 24”x25.5”x24” with a Dayton 460HO driver tuned to 20Hz powered by an NU6KDSP. I chose this design to complement my pair of PSA V1801 subs which perform very well in my space given their small, spouse accepted footprint in a 5.5Kft^3 room.
Here’s a link to the Martysub FAQ page which has thousands of helpful posts and numerous unique subwoofer builds.
I chose the 460HO driver partly because the Dayton Ultimax 18-22 is usually out of stock for a month or two, and the performance above 25-30Hz is very similar between these two subs in a smaller enclosure. The UM18-22 would net an extra 3dB output at 20Hz with double the power requirements of the 460HO, but the UM18 driver loses a lot of its ULF potential in only a 4.75ft^3 enclosure. I also felt the 460HO is a better match to my PSA subs based roughly on driver specs.
If the weather cooperates, I’m getting started on the MDF cuts today! More to follow.
New console I just finished to fit both V1801 up front, and allow room for the Martycube in the back of the room.
Let the cuts begin!
Boards all cut down to size with only a few mistakes that needed redone, but with so many pieces I was able to repurpose them. It took a little longer than I had imagined using only a circular saw, but once I found a rhythm the cuts came out great.
Time to start the box assembly! Might need a nap first, haha.
It’s a box! Clamps, a brad nailer, and glue make it pretty easy to start assembling even if you’re solo; I think getting the first few walls up would be a pain without clamps by yourself. This is just a dry fit to see if everything is square...it is! I got lucky and managed to make all the hand cuts with a tolerance down of about 1/32” or less, fingers crossed the rest of it fits together this nicely.
And now to frustrate myself beyond words, I was in a hurry or just didn’t give assembly much thought and believed the dimensions made the Martycube slightly taller (which is wrong, it is more wide than tall), and so I started to put the first four walls together incorrectly and permanently bonded them with a brad nailer and PL premium glue before realizing the the port rails, top and bottom sure do look off with this orientation when dry fitting those next few pieces.
WARNING: If you’re building a Marty, do not put the box together like this or you will be sad and waste a half sheet or more of MDF to start again.
I’m glad it was just the first few walls I screwed up. Of course, they’re the largest panels and the way I had my initial sheets of MDF ripped to transport home, I don’t have enough 2x2’ pieces left to cut from, so that’s essentially most of a sheet gone to waste.
I’m working the next three nights, but I’m determined to run to the store at 6am today, have another sheet cut down, and throw together the first few pieces so I can work on them in between to have little MC (Martycube) ready to crank some bass by next Tuesday or Wednesday.
Time lapse video of a forum member assembling a mini Marty. Watch this first and it may save you from making the same mistake.
Ok, second attempt at box assembly:
Very loosely dry fit more than just the first few walls...check. Looking like the correct way to piece together Marty
Glue, clamp, brad nail the bottom, sides, and back
Port rails and paint
Before inserting the large port bottom and top boards, you may want to run a bead of caulking around the outer seams. I used PL Premium construction adhesive on nearly all the seams, so I didn’t feel it was necessary; I can see why people love this stuff! It’s messy, but very effective at expanding into gaps and creating a strong bond. I’d guess you’d need CNC cut precision to slap most of these boxes together without some sort of gap filler/only wood glue.
Dry fit the front baffle during curing to ensure a proper fit.
Top down view, build on hold for the next few days
REW sweeps and burst tones at fairly low output from 10-150Hz, driver sounds and looks great!
Baffle cut out will be recessed with 3/4” ply on the inside for support, definitely helps to have a circle jig
First cut the circle is 16.6875” which is almost perfect for the 16.69” baffle hole for the 460-HO. Better a hair over to prevent sanding an overly tight fit, but I think I’ll take it.
Counter sink a couple screws into a board below it to keep the cut piece from moving without having any clamps in your way along the edges
For a first time builder, this is definitely a slow process from scratch, but appreciating the intricacies of DIY builds is partly why I took on this project. If I’m lucky, I may get everything done by the time I have to return to work with little room for installation, calibration, or listening sessions. I can definitely see why sealed subwoofers with precut flat packs can easily be churned out in a day or two with minimal work...if only my room was smaller.
Round over front baffle, used 3/8” here. May do 3/4” on ports and box edges
Bracing and hopefully the rest of the box will be done today with just the lid to put on tomorrow and then finishing. Running a couple days behind my completion goal, but that’s ok.
Yay, the front baffle is perfectly square!
Majority is finished, feels good! Between work and previous commitments it will be the next couple weeks before it’s finished.
Speakon connector hole using 7/8” bit was a hair small, hole made to be 15/16” before it’d fit
Hope to finish the innards, drill the driver screw holes out, add insulation and get the top on today!
Continued in post #2