is there a L:W rule for a port?

[ppiflat10s 3]

I have plenty of room for my overall volume, but fitting 3 10's and a port on the face is my challenge.

I am going to have a box of around 3.25-3.75 ft^3 tuned to around 35. I was going for around 60 in^2 port area, my inside dimension is going to be 30.5 so that leaves me with a port that is 2" tall by 30.5" wide. Ive already done the math and have the depth on the box to easily fit the port length, but is there any reasons against a port of this shape?

I thought about using about 4-5 4 inch round ports, which is either 48 or 60 in^2, but with either route I need to have ports longer than will fit inside the box, and I will not run an exterior port because this is my daily car and I really dont like the look of a setup like that, if I used 4" PVC, can I use 90's on each port? and just calculate the port length like I would with a square port?

the square port would be the easiest to build, but I sort of want to try the round port again, I used to use a jig saw to a tracing of the pipe, and obviously never got the greatest result. now that ive built some more, I am going to do a double baffle again, and use a hole saw on the first baffle with internal bracing holding the port and a flush trim router bit on the front baffle to get a perfect fit/nice clean look.

also, if I was to coat the box in herculiner, would it be bad if I covered the .75" visible MDF edge of the outer baffle? I could carpet the box, but not sure on what Id do with that unfinished edge, maybe Ill just herculine that part and carpet the rest. should start on the box early next month, and Ill post some pics while Im at it.

its for a trio of PPI PCX102 10" subs, I got 1200 watts available(obviously will have to turn back the gain a bit) and am going to continue designing my ported box unless someone says I should stick with a sealed box for these.

my box as of now will look like this - either - A) bottom ports will go to the back and turn up, top ports to back and down, or B) bottom ports to back and turn in, top ports to back and turn out.

[lithium 358]

looks ok, measuring like that is fine. i think there is a rule thats says u dont want the port opening to close to the rear of a sub or get to close to the walls... just keep them like 4 inches away from anything if you can.

i think square ports are sexier, thats just me tho. but round flare ports would be even nicer!

[KU40 173]

You don't want the port to be that long of a rectangle. The general rule is to keep the ratio under 1:9 for width:length.

If you use aeroports you won't have to use as much port area, which will make the ports shorter. I'd venture to say that you could get away with three 4" aeroports. Try that for port length and see if it will fit in the box.

[REVpuggie 23]

I'd opt for a slotport that would stretch the entire or most of the width at the bottom of the box , and make it nice and big , as stated above keep the ratio 1:9 width / height. this wouldt probably result in less chuffing than 4 aeroports .

[iamamp3pimp 34]

1:9

[ppiflat10s 3]

but if I have the port 30.5" wide, and use the 1:9 rule, Id need to have the port basically 3-3/8" tall, so Id have 103 in^2 port area. box only 3.75 ft^3 max, so thats WELL over the 16 in^2 per cube. its actually getting close to double. and when you say aeroport, is that just the term used for a round port, or is it different than running pvc for the port?

also, about not having the port close to the back wall, I know if it goes straight back and ends it needs to be at least the diameter of the port away from the back wall, but if its making a 90, it can be at the back wall, right? because a slot port always turns at the back wall(at least mine always do and the ones ive seen always do too).

and 3 4" ports would only give me about 8 in^2 per cube, isnt that a little small?

and about the round flared ports, wouldnt really be a flare of any decent size, but I am going to use a roundover bit on it as well, and was going to try and carpet it and somewhat stretch the carpet into the box at the port and staple it from behind before I slide the port up against it the final time.

I wanna make this box my crowning achievement of box building so Im going to take a while designing it and figureing the best way to make everything fit together and end up like I want it.

[pipes 1]

Aeroports refer to round ports with a significant flare at the end.. take this for example http://www.parts-express.com/pe/showdetl.cfm?Partnumber=268-348

The term "back" is being used generally when said to keep the port away from the back.. just keep the opening of the port inside the box a good distance away from any obstacle (back, side, top, driver) that could interfere with the air moving in and out of the port freely.

[ppiflat10s 3]

alright, well, I am just going to use abs or pvc, not going to buy those ports. so I'll try to run 4 4" ports and see what heppens, the depth of the box vs the depth of the port makes it so that when the port ends it will be a good distance away from the wall its facing.

its going to be front firing, back seat folds forwards, and I am not going to 100% seal it to the panel behind the seat, but I am gonna build a little frame angled to the back of the seat and plumb on the back of it and slide the box up against it.