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Discussion Starter · #1 · (Edited)
A few months ago I embarked on a journey to find a subwoofer that would meet my 50% music 50% movie listening needs. A high output was another must, since the room in which it will be playing is rather large. I did some homework ran WinISD simulations and decided a B&C 21DS115 was my best option. I added an AT screen to the room, so expansion plans had to be tweaked and the Stormbreaker Cube (or more accurately the Cube XXL) was born. I chose the name of Stormbreaker since it is a dual purpose implement, hammer and axe. Stormbreaker is rather powerful, but remember, aim for the head.

New Cube version, see this link for details - https://www.avsforum.com/forum/155-...1ds115-subwoofer-solution-2.html#post57111406

~10cuft internal volume, ~18hz tune.
















Original cabinet, internal volume is ~11 cu ft with an ~18hz tune.




















Blue - Original enclosure SPL 1m 1700 watts 2nd order high pass filter 17hz.

Red - Cube enclosure SPL 1m 1700 watts 2nd order high pass filter 17hz.




A big thanks goes out to @LTD02 for his design work on this project!
 

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Discussion Starter · #2 · (Edited)
The list of things

Tools:
-Drill
-Impact driver
-Circular saw
-Jigsaw
-Orbital sander
-Tape measure
-Carpenter square
-A long straight edge level is handy for a circular saw guide
-Clamps, lots of clamps (at least 2x 36" clamps and 2x 4" clamps)
-Compass of some sort
-Crimp tool for the disconnects
-50 grit black zirconium sandpaper for the orbital (it will save a lot of time on panels and bracing that do not line up perfectly)
-60 grit sanding sponge (good for sanding inside the baffle cutout edge)
-80 grit aluminum oxide sandpaper for the orbital (great for finishing up vinyl drywall putty and taking material off at a slower rate)
-Wood file
-Knife
-Putty Knife
-Scissors
-Things that are not too large and weigh a lot
-Safety glasses
-Dust mask

Parts list:
-B&C 21DS115
-Two sheets of 3/4x49x97" MDF
-3 or 4 2x4" for bracing (there are many ways of doing this) also they are used behind the baffle to make sure that 21" driver does not go anywhere
-Neutrik NL4MPR Speakon Connector 4 Pole Round Chassis Mount
-2x Neutrik NL4FX speakON SPX Series 4-Pole Cable Connector
-Gold 12-10 AWG 0.187" Female Disconnect 5 Pair (Neutrik terminal)
-1/4" (12-10) Nylon Insulated Female Disconnect Crimp Terminal Yellow 50 Pcs (for the sub terminal)
-Parts Express Speaker Gasketing Tape 1/8" x 1/2" x 50 ft. Roll
-12awg OFC speaker cable
-Acry-Tech DuraTex black 1 gallon
-number 7 2" screws
-number 9 3 1/2" screws
-3 or 4 tubes of Loctite Premium (I used the 375, but 3x is another good solution)
-Mattress foam (I used a twin from Walmart, but discovered later the same thing can be found at Meijer for have the price)
-I tried two different spray glues on the foam with poor results, just put some PL on the foam, it will not go anywhere
-Rust-Oleum 2in1 black matte spray paint for inside the port
-Vinyl drywall putty


If I find more things lying around when I cleanup my work area I will add them to the list!
 

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Discussion Starter · #3 ·
Two full sheets of MDF barely fit in a Dodge Caravan.



Unfortunately I messed up cutting the hole for the subwoofer in the baffle and it will require a take two.
 

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Discussion Starter · #5 ·
Is the cuttout for the driver off center? What was wrong with it?

The diameter of the hole came out too large using a jigsaw and a makeshift compass. I was off enough 4 flange holes were half over of the edge of the baffle. Two of my friends that have the wood working experience looked at it and said not salvageable.



I ordered a compass that can make a 20 inch hole, that should take away some margin of error. Also a buddy said he could route it out if I made a smaller diameter rough cut first with the jigsaw. I will cut the hole at 19 inches then check the fit and go from there.
 

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Cancel your order on the 20" compass.


Find a scrap piece of MDF that's at least 11" long. Drill 2 holes in it, one at one end. Then measure 10" to the other end, or whatever you need the baffle cutout to be, then drill a second hole. Locate the center of your baffle, I use the "X" method, and then screw the scrap piece to the center. Put a pencil through the second hole and spin the fixture around to draw a circle.


Takes 10 minutes and is essentially free.
 

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Discussion Starter · #7 · (Edited)
How much clearance would grill fabric need from the sub? The plan is to remove some of the toddler market appeal.



Blasting toys from the vents adds another layer to the demo experience. You can literally feel the Ninja Turtles coming at you.
 

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How much clearance would grill fabric need from the sub? The plan is to remove some of the toddler market appeal.



Blasting toys from the vents adds another layer to the demo experience. You can literally feel the Ninja Turtles coming at you.


Enough so the excursion doesn’t hit it.


Sent from my iPhone using Tapatalk
 

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Discussion Starter · #10 ·

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From reading the product details from PE, it says both parts need .5in deep hole. The female part needs a 9/16dia hole, and the male part needs a 7/16dia
 

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Discussion Starter · #12 ·
My apologies for the poor wording, how far in from the edge of the cabinet? Would running that large of a hole in the side panel be a bad idea?
 

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My apologies for the poor wording, how far in from the edge of the cabinet? Would running that large of a hole in the side panel be a bad idea?
Where you place them will depend on how much coverage you want from the grill... if you want the whole front covered, then they would go near the edges. Since you have doubled the front baffle, a 1/2 inch deep hole is not a concern.
 

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Where you place them will depend on how much coverage you want from the grill... if you want the whole front covered, then they would go near the edges. Since you have doubled the front baffle, a 1/2 inch deep hole is not a concern.

I agree with what he said. A .5" deep hole in a 1.5" thick baffle would be fine.


And for the actual size of the grill, personally, I would build a rectangular frame, 29"x39" and chamfer or round the outside edges for the speaker cover. I would build it out of scrap MDF. This would leave a perfect 1" reveal around the grill, but still completely cover the subwoofer. I think that would give it a very professional finish.
 

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Discussion Starter · #15 ·
Progress update

I finished the port assembly more sanding than I had hoped for. 3x 16th inch errors make a mess somewhere else in the cabinet. The back panel is a little long, I will have to sand that down. The baffle cutout went so well I could not be happier! A few seconds of filing the driver fit into the outside baffle sheet tightly and no gaps on the inside sheet.



I picked up this jigsaw on Amazon - https://www.amazon.com/BLACK-DECKER...28107&sr=8-1&keywords=black+and+decker+jigsaw


The variable speed control is more fine grained than I anticipated and made precise cutting a breeze. I had the curve control set at three.



I am hoping to get the bracing and baffle in this weekend :)
 

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Discussion Starter · #16 ·
Sanding took awhile today. I had to bring the front port down about 3/16th of an inch on one side and the back panel was an 1/8th of an inch too tall. The 2x4 bracing is all installed, minus the two braces that go on the top panel. The baffles are now glued together and curing. Newbie notes - PL goes fast and cab of this size goes through #7 2 in. screws at high rate. Luckily I had another large box of screws lying around from a fence project.
 

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Discussion Starter · #20 ·
I tried sanding the PL for a few moments and realized nothing was happening. I used my pocket knife at shallow angle, did a nice job of cleaning it up.
 

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