Looking for DIY sub advice, volume 2

Hey everyone, I created a thread a few months ago looking for some help and it kinda died out.

I have an RF-83 system currently without a sub. I was looking at greeting a PB-13 ultra and when checking it out on the forums people were saying that for that price point I midaswell build my own.

In the original thread I got a recommendation of using a UXL-18 (from beast, who I'm sure will chime in ). They are currently out of stock. Do you think I should wait for them to get back in stock of do you think there's a better option?

The room it will be going in is 19ftx14ftx9ft.

The space I have for the sub is 30in deep x 30inch wide x any height. The width could go as wide as 40 inches. I'm hoping to get something around 2ftx2ftx2ft.

I'm planning on building the enclosure out of mdf and veneering it. I plan on flush mounting the speaker. I would assume I'm going to need to use 1 inch mdf. 1" mdf is a bit difficult to find, so am I better off gluing 2 1/2 mdf sheets (I've heard gluing 1/4" and 3/4", is there a difference)? Also, for the inner piece of the flush mount (basically the part the sub will actually mount to), should I cut the hole out and leave the rest of the mdf so it would be like an entire second layer on the front, or is it ok to just cut it into a 3-4 inch thick ring and gluing it up (not sure how much sense this makes)?

Last question, what do you guys recommend doing for the bottom/feet?

Forgot to add, it's used mainly for music, then gaming, then tv and movie watching

I was originally going to go with a PB-13 ultra.

I'm hoping to not spend more than 1000 on the driver/amp but could go higher.

I don't have enough space for multiple subs though so I'm trying to get the most bang for my buck out of a single sub

They are around 2k but can be found for cheaper sometimes. I was planning on spending around 1000 but I'd go higher if it gets me more bang for my buck.

I was planning on using an ep4000 for power.

You'd take the dual D4's versus a single UXL-18?

Thanks. Good to know 3/4 should be good enough

That's impressive.

I'm not in a big rush, so if I can get more out of a uxl-18 than something else I may wait for it.

Looking around online I'm trying to see if I should go with a 6 or 9 cubic foot box (assuming I use a uxl).

It looks like a 9cubic foot box would be 25inx25inx25in tuned to 18hz. It would require a 2.5inch x18inch port size with a 36" port length.

The 6 cubic foot box would be 22inx22inx22in tuned to 20hz and would require a 2.5 inch by 15 inch port with a 37" port length.

It looks like they both hit xmax around 13.5hz.

Is the benefit of tuning at 18hz significantly better than going with a slightly smaller box? Would the dimensions need to be adjusted a bit to accommodate for the port and bracing?

Quick question when determining the volume of the box. To get it I assume it is measuring internal dimensions (so if it's 24x24x24 with 1" mdf, it would technically be 22x22x22). How is the port/port length taken into account?

I'm gonna try and start working up a design for the UXL-18

Wow, that's amazing. Thanks!

So, using that calculator with a 24"x24"x27" case, a 2.5"x18"35" inch port size and a single 24"x24"x3/4" brace with 5"x5" square cutouts came out to 6.353 cubic feet without the driver (no idea what the volume of the driver is).

Does that seem right? Would I need more/less bracing for a box that size?

I've been messing with WinISD but I'm not sure what I'm looking for.

Anyone with more experience have any suggestions about what tuning/port size I should go with with a 9 cubic foot box (using external dimensions and not including any internal bracing, the port, or the driver)?

Bumping this up, hoping someone with more knowledge than me can help run the numbers

I was hoping to get into the teens. I'm not sure if there is a sweet spot to shoot for in terms of tuning though. I'm sure there is a point of diminishing returns.

I'm hovering around a 9-9.7 cubic foot box (using external dimensions). I haven't quite figured out the exact dimensions to use yet. Would bracing have a significant effect on the tune?

Once I get a more solid idea of dimensions I'll draw something up and post it back up here to see if it needs more bracing

It's 9ft3 using external dimensions, ~3ft is removed if you take into account the port and bracing (right?).

Which port dimensions would give the 15hz tune?

Is that tune for a 9ft3 external volume?

Is the port considered part of the total internal volume or is it subtracted from it?

Using the (simple) example I used before with a 9 ft3 external volume came out to ~6.3 ft3 internal volume taking into account some bracing and subtracting the port size.

Would that still be able to get to 15hz?

Sorry for all the questions

I should be able to increase the external dimensions to 25x25x30 (30in is about as far as I can go on depth, 28in is a bit more comfortable)

What is the tune with the 25x25x28 box? I'm trying to see how much of a gain it is/if it's worth it, as it's gonna be pretty tight on space

I think I might whip up a design with cylinder ports and one with a slotted port. To clarify, to get the same effect of the 2.5"x12"x43.5" slotted port I would need 4 3"x43.5" cylinder ports? How big would the cylinder ports need to be to use 3 (instead of 4)

Also, about the tuning, with the 25x25x28 box the tuning would be around 16hz and with the 25x25x30 it would be around 15hz?

Thanks again for humoring me....

Thanks, that all makes sense, but what do you mean three ports would need to be 32"? If 4 ports need to be 43.5" (with 3" port) wouldn't using 3 ports require them to be bigger/longer?

I'll start whipping up a few front cab designs and see what looks best