sub box math, am i doing it right?

I don't know where you got the idea that the inside corners of a subwoofer enclosure need to be rounded or angled or treated in any way, but they do not. IN GENERAL, a smaller enclosure will increase the subwoofer's power handling slightly because it helps keep it from exceeding Xmax. But the effect is small, and the more likely effect from smaller systems is higher resonance frequency and a "bump" in the output often causing a boomy system. In a vented system, you are foolish to make it smaller unless you absolutely have to. What "12-16 multiplier" are you talking about? And lastly, did you decide how you plan to brace the enclosure?Support the12volt.com

2 posts back i posted a new set of images from my redesign of the bracing. if you think that is good then ill go forward, let me know what needs to be changed. the 12-16 is the multiplier. 8 cubic feet * 16 = 128 / port width (34.5) = 3.7" max port height. and *12 minimum port hight for its size. here is a relink to the redesign: https://imgur.com/a/d3ZrJ redesign my thoughts were to try and keep the box as close to 8 cubic feet (max for this sub) as possible with out going over. you mentioned the edges dont need to be cut in or rounded, ive seen many sub box videos where builders swear by this processes so thats what i was thinking of doing. they coat the inside with resin to add strength so i was planing to do the same, unless you feel its a waste. i was planing to router every edge to a smooth rounded surface to help eliminate any rough air movement, is this a good idea?

Your links do not work. Use the forum's image up loader. Coating the inside with resin is a great way to both add strength and seal the enclosure against air leaks. But rounding the corners or the edges is not necessary. "Rough air movement" is not an issue. Rounding the exit edge of a port can help reduce port noise (and it creates a small flare which changes the size of the port - makes it a bit longer.) Be sure if you do this you model your system with one flared end to make sure the port is the correct length. You said: "the 12-16 is the multiplier. 8 cubic feet * 16 = 128 / port width (34.5) = 3.7" max port height. and *12 minimum port hight for its size." Where did you get that and what do you think it calculates?Support the12volt.com

i just tested the links and they work, must be a browser issue on your end. *shrug* i know how wide the port is given the width of the box, the formula calculates how high the port opening should be, it gives me the Y for X of the port surface area here are the pics:

The links work fine from your computer because you posted them, but the URL is incorrect in this forum. You are posting this: https://imgur.com/a/d3ZrJ but the IMG tag must end with a graphic file type descriptor. In any case, sounds like you are calculating the area of the port opening. Fine. The pics you did post correctly show a well-braced enclosure. Go for it.Support the12volt.com

sweet, ill look to build it up this week. im picking up a ZX2500.1 in a swap for my current ZX1500.1. we shall see if the sub can handle the extra power, if so then great. if not then i suppose ill buy a second :P

Now, that's braced. Good job!It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

im glad you approve. this has been a long learning experience in just the design... cant wait to jump off the learning cliff during the physical build

PROTIP: pre-drill all screw holes or else you will split the MDF. use wood glue or liquid nails( i like liquid nails between my sides and it seals a box great) also to answer your question about the port opening being 3" vs 3.5", considering the overall size of the port i dont think you would see a difference with any port noise, but keep in mind that going with a bigger port also means it must be longer to keep the same tuning. so the size you ultimately choose to use needs to take that detail into consideration. personally the biggest port ive made so far is for a box for two 18's that is 16 cubic feet and double layered the whole box. the port is 4" x 45" x 28"(not sure about the length). either way, its huge and the air that comes out of it is enormous. big ports definitely have a nice effect that comes with them.

well my plan is to follow tores tuning calcs and keep the back of the box only screwed on. then tune by adding varying lengths of wood brining the port down into the box and lowering my tune until i hit what i feel sounds best. i expect that a 36hz tune is going to be damn close to what im looking for according to my research. i will predrill, use wood glue or gorilla wood glue and then resin the whole box. i have read that liquid nails has to much give to it and thus is a poor choice for heavy boxes with loads of power. there is so much conflicting information and supposed "facts" around about car audio that this whole processes has been just one cluster F*** of opinions. it seems that for the most part you just have to get as close as you can in the middle ground and then try things out for your self. i cant tell you how varied the responses to questions ive gotten between car audio install forums, 12 volt forums, and SMD forums. not to mention the youtube box builder channels... then on top of that some craigs list audio installers have yet another recommendation and then car audio installers i worked with at circuit city install bay have even more "facts" that contradict. quite the learning processes i have delved into here