Dimensions for sealed 18" sub box - Page 5

The boxes posted don't show the outer baffle, only the first layer baffle that drops into the box. The 2nd layer outer baffle will have roundovers. The only reason I didn't show the outer baffles on the larger boxes is because they'll have to be cut from the second sheet of MDF and I didn't want to waste prototype money just showing a baffle.


I took photos of the new sealed box for the 18". I just have to download them and post.

I can look into some bigger boxes between 6 cu ft and 7 cu ft but they'd have to be shipped in 2 separate boxes. I'd be guessing to say they'd likely be pushing around $175-$200 counting shipping for something that large and heavy. In reality, I'm not sure that's a bad price figuring 2 sheets of mdf and shipping around 100+lbs.

I'll find out though, but it will likely be a week or so before a prototype can be cut.

The same way you would with any other baffle you'd install on the front of a speaker. On these, you'd put glue between the 2 layers, and then clamp it in place. I don't think it will be too hard.

Some people might prefer to use screws and pilot holes along with the glue.


I'm thinking about having the outer baffle cut about 1/32" bigger in both directions so the edges could be lightly sanded if needed. Or have enough of a lip to match up with some veneer that someone might add later.



CNC machines are accurate to 1/1000 of an inch. I've taped these boxes up and they line up real nice, but even the thickness of glue or PL adhesive could cause you to need some light sanding. Basically they can be lined up perfect, but if you run your finger over a seam, it could still need some very light sanding. There's no way around human interaction causing the need for light sanding when dealing with wood.

A clamp too tight, or not as tight as the next one can cause a seam to be off by about the thickness of your fingernail. There's no way around that. But sandpaper will knock that down in a minute. These will be far more accurate than things cut on table saws or other home gear.

Okay, the new box is on the right. Notice how it was made taller so that the bracing could be shifted closer towards the middle and still leave room for the big magnets. This new design seems to make more sense. The "shelf" for an extra window brace was removed because I'm not sure it's necessary with the new design. Maybe I could put that shelf idea back in the braces so that people have an option to add it if they really wanted to. Let me know what you think.




This photo shows the height difference. Basically the one on the left went from 23x23x20 to the 22x22x22 on the right. The ole switcheroo.

There will be a box between 3.5 and 4 cu ft. I figured it would be more used for 15's. I don't have my notebook, so I can't recall the sizes I wrote down. Believe it or not, to get around 3.75 - 4 cu ft would only make the box shrink 1" to a 21" cube versus 22". So it's a very minimal difference and I'd rather just get one or the other made up. I don't care which you guys decide on.


The 22" cube with the double baffle comes in at 4.8 cu ft gross. But after you subtract off bracing, it's closer to 4.5 - 4.6. I'm not sure how much volume those big drivers take up, but I'm guessing the volume the driver sees would be around 4.25?? Any ideas?


I only had 5 of the 22" cube models done for prototypes, so if you guys think a 21" cube makes more sense, please let me know before a bigger number is made.

Some of those big horns in the Autotech group buy from Poland need to be shipped on a pallet once I get them. Most of the pallets were between $175 - $200. I think I've helped with about 5 or 6 of those. One did come in around $250 because they lived in an unusual place.

A pallet would be the only way to save on shipping a larger number of these because I don't think FedEx gives discounts just because 8 packages get shipped to the same location. At least I don't think so. But I can always make a quick 5 minute phone call to find out, no big deal.

I wouldn't have to package them in shipping boxes, so that could save a little there.

If that's the case, then the 22" cube should give about 4.25 cu ft net for the LMS and other big 18" drivers.

If anyone wants to be the guinea pig and try one out, let me know.

Besides the current shape for the other subwoofer boxes, I'll try to get some regular cubes for the 12" and 15" models by the end of the week.

By the way, if anyone has any recommendations for boxes designed around certain drivers, please let me know so I can get that done too. I'm close enough to PE that I can drive there and pick them up to make sure it all fits properly. Maybe even get some kits going?

Does anyone have any designs for smaller boxes with slot ports?


Having specific designs would help out at this point because I'm not much of a sub designer.

Anyone good enough to draw up 2 slot port designs? I don't know enough about slot ports to figure anything up right now.

Maybe a 4 cu ft and 3.5 cu ft? Tuned around 18hz or so? Would it be better to port out the back or the front?

I read that the Dayton 315HF 12" and the Lab15 would work good in a slot port design around 3.5 - 4 cu ft.

I want to get 2 more prototypes done, then get a price for each one. Reason being that the enclosures that need part of an extra sheet could have the rest of the sheet used for a 10" enclosure. So that will likely change prices and keep them lower. I want to make sure everything is accurate before putting out the numbers.

The 19.5" cube should be done tomorrow. With the double baffle and the same cross braces as the larger 22" cube, it should be right at 3 cu ft net volume.

Okay, here's photos of the first 7 prototypes along with the 2 new ones I said I'd get taped up today. I had to get up on a ladder for this photo.

The first 2 on the top are about 4.25 and 4.5 cu ft net volume. The 3rd one on the top is about 3.5 net. Middle row: First and second were taped up today. 3 cu ft and 2 cu ft net. Next is 2.5 cu ft. The bottom one is 1.25 cu ft net.





I like this following one a lot. Not extremely heavy, but very strong. It's a 3 cu ft cube. Outer dimensions are 19.5" with a double baffle. Taped up in less than 5 minutes.




Here's the 2 cu ft cube. 17.5" with a double baffle:




Here's the double baffle on the 2 cf. THERE WILL BE ROUNDOVERS This one has the driver recessed only .5", so there's a full 1" behind the frame.




I dropped in a Dayton 12" driver to see how it looked.