More port area (more tubes) requires a longer length to retain the same tuning.
Box tuning is directly related to its size, the port area and the port length. In order to maintain the same tuning, if you change one part of the equation you need to change the others to balance things out. It just so happens that in acoustics, port area and port length are inverses of eachother. That is, when one increases, the other needs to decrease for tuning to remain equal.
Usually you want to keep your ports close together. I don't have anything to back this up, but I feel like if your ports are scattered around the box, there's going to be like a constant struggle for the air flow since it's going to be moving in different directions. For a daily setup, you probably wouldn't notice anything. Maybe some slight port noise and a minor loss in efficiency that would show on the meter. I'd play it safe and keep them close together personally.
You can use 3 4" aeros, or a single one that has the same amount of area and it would be the same length. So instead of 3x 4" tubes, the math works out to use a single ~7" port, which could be made with wood (look up octoport). A single port is more efficient and will cost you a lot less. Unless I misunderstood and you don't actually have the space to mount a port that large.
I will look into making an octoport, as I do have enough space to do so. I had never heard of that type of port before, but, I certainly can make one. I thought the only choices were slotted, or round ports, as that is all I ever hear about, or see for that matter. Heck, I learn something new every time I am on here. Also, is the seven inches from opposite flat areas, or from opposite widest corner to corner?
Thank you. I completely understand. I really appreciate your help.
Okay, I was just checking, as it is obviously easier to build a square shape, than an octogon shape....as I do not on a table saw, just a skill saw, and a jig saw. I'll eventually get it though.
