new box for alpine type r

Equipment: 1 Alpine Type-R 1542D (15" dual 4Ohm coils) 1 Alpine MRP-M1000D (1000Wrms @ 2Ohms) 1 Honda Civic hatchback Now: The current box is about 2.5 cu ft and tuned at about 40Hz I'm content with the current sound, I just know that there's more in my equipment than I'm getting. When playing the Low lows, you can feel a "breeze" of air coming from the sub, but you cant hear (feel) it as much as expected. And with the current 3" diameter port, I have terrible port noise at these low frequencies. Goal: More Low frequency SPL. No port noise. Alpine says 2.25 net internal with 22.5" port area, But I was thinking closer to 3cu ft net with 44" of port area.... I know most box builders don't like to deviate anymore than 10% from manufacturers specs, but for my particular goal, does this seem ok?? (sorry for the long post, Just trying to get it all in there) EDIT: New design will be Slot Vent (If that changes anything at all. lol)UNLABELED Custom Car Club President

What frequency are you planning to tune to? Going that large is okay to do with that sub. They tend to perform better in a larger enclosure and especially for what you are looking for.

Well Im thinking of tuning at 30.... Think I should go lower? I Really want the Lows but dont want to loose All of the outputUNLABELED Custom Car Club President

Another Question.... Wut are the advantages of puttin 45's in the corners of the port?UNLABELED Custom Car Club President

Your 40Hz tune now is why you are lacking low end and your 3 inch port is only 7 square inches of port are, which is why you have nasty port noise. Simply lowering the tune will put you more where you want to be. 30-32Hz should be good and around 30 square inches of port area if your going 3cu.ft.. Doing 45s on a port fold simply helps to channel the air better. Making it less turbulent and alowing it to flow more efficiently.

I've had good luck dividing the port up in two and adding additional length to it. That way the sub can sit in the center of the box and each port can fire to each side of the sub. I think it fills the sound more evenly and it looks a lot better to see the sub centered. Here's a old sketch of the basic ideaThis is what I do for FUN!

This is Wut Ive got so far.. it should be right at 3 cu ft after bracing total port length of 35 inches (port 2.5 x 18.8 x 35)UNLABELED Custom Car Club President

Ianarian, I like your symmetrical design, but i simply dont have enough space to get 3 cu ft net volume in that box in my little hatchback. Maybe Ill try somethin like that after i convince myself that my back seats are un needed UNLABELED Custom Car Club President

WAY to much port area. for 3 cubic foot net you only need 30 square inches of port area. You have 47 there. Also are you figuring your Net right? Total GROSS internal volume minus port, driver displacement and bracing. Im getting 32.2Hz tune if you have correct Net of 3 cu.ft though. If that is a gross of 3 cube your tune will be much higher. Post your measurements and i can double check them, but i can tell you now you don't need that much port area.

28 x 16.75 x 20 (external with double baffle on front) port length one = 13.5 port length two = 12.75 What is the disadvantage of having too much port area?UNLABELED Custom Car Club President