Building new box tomorrow. End correction question, and suggestions

[chuey_316]

Building a new box for my RE 18hc tomorrow. Was going to build another abc, but decided to go back to a regular ported box for now. The box will be 7.6^ft net powered with 1200w. Unsure of the port area as of yet, but I'm thinking somewhere around 100-120sq in. tuned around 34hz. This is just a dd, and I listen to a mix of rock and rap. The port will be a slot port, and will use 3 walls of the box. Port will be 15" high, and i'm undecided between 7, 7.5, or 8" wide.

The end correction would be half of the smaller port dimension, correct? Also any suggestions on the port area, or tuning? My old box was 8^ft with 92.8sq in, with the same amount of power. Can't remember the tuning off hand, but it was somewhere between 34-37. It had decent sq and it was pretty impressive. The large side windows on my 1st gen 2dr blazer flexed a good bit.

The new box will be going in a 2nd gen 4dr blazer, and I'd like it to get just as loud, or louder, while still retaining some sq. My goal is about 60/40 leaning more towards spl.

Last question is how far away from the rear wall should I aim to stay with the port? The box will be 24" deep, and the port will need to be around 17-20" deep with a 7.5 or 8" wide port.

Any suggestions on tuning or port area welcome.

[alaskanzx5]

You want the port opening on the inside of the box to be at least an equal distance from any wall as the port is wide. So if the port is 8" wide and 20" long in order to keep it 8" away from the wall you will have roughly a 4" extension off the port turning. The port would be L shaped.

[chuey_316]

Thanks. Does that account for end correction as well? I didn't factor that into the length with my 17-20" statement. The physical length of the vent will be between 13.75 and 15.5, but after factoring the end correction, the overall vent lentgh will be longer.

Would I still need an L due to the end correction, or does the rule generally apply to actual physical length?

[alaskanzx5]

I've never looked into end correction.

I've always just used Torres, winisd, and online tuning calculators to get a rough estimate of how long my port needs to be for a certain freq.

Hopefully someone that knows more about it will chime in.

[chuey_316]

I ended up with 6.42^ft net, with a 15x6 port tuned to 35hz. It's about 1 cube smaller that the old box, and tuned 2-3hz lower. I'm hoping that it will compare well to the old box. I think it should. The old box need more port area. It was only 10.5-11sq in per cube, and this box is 14sq in.Sealed the box with liquid nails, and will let it cure overnight. Just need to drop the sub in, and install a terminal and it's ready to test out.

Thanks to everyone for the help with the questions over the last couple days. It's been awhile since I've built a box. Was worried that some of the things I thought I remembered may have been wrong.