thebman
Hi, I am helping a friend design his first subwoofer system and am in need of some advice. I have built several sealed boxes in the past but this will be my first attempt at a ported enclosure. We have a total of about 6 cubic ft. of space to work with, and will be using 2 12" Alpine Type R-1242D subs in this box. They will be getting about 300 watts RMS a piece. I know this is very low for these subs, but this is all we have to work with right now, which is partly why we want to go ported, so this power can be used as efficiently as possible.

I would like some advice from anyone with experience with porting these subs, namely how much cubic ft. of space would be good for these subs ported, and the size the ports should be. I was thinking of using slot style ports, but I definitely wouldnt rule out round ports either. Round ports seem like they would be a bit easier to use anyway, as long as I knew what size to use. I would like to know if I should be using a single chamber and a single port for both subs, or 2 separate chambers, each with their own port.

I am looking for a box and port size that will be efficient, with a frequency curve that wont be too peaky. Looking for a good balance of Smoothness/SQ/SPL. My friend mostly listens to Rap, so a system that performs well in that proper frequency range would be great. Any advice that would help me would be welcome. Thank you.

[ 03-09-2010, 07:16 AM: Message edited by: thebman ]
Quote 0 0
thebman
Oh, I wanted to mention that if I were to go with slot ports, they will most likely be ran along the sides of the box, firing out in the same direction as the subs. If I do go with a slot port, the box will be about 13" tall, so the ports would be about 11 1/2" tall, and would need to know how wide to make them without having bad port noise. I have heard that using the wall of a box as part of a port effects the port area somehow, although im not totally clear on how it affects it. Also if it matters, the subs will be in a lancer, and will be facing torwards the back of the trunk, with the ports facing the same direction. Is this ideal?

I like trying to figure out this kind of stuff on my own, but if someone could go as far as to give me exact specs for building the type of box I need, I wouldnt complain I have tried playing around with winISD, and just about everything in that program is like im reading a foreign language. I just dont have the understanding to use that program.

I can do simple calculations for square ft. and cubic ft. where needed, and I can measure out sheets of wood to build a box, but I just need a place to start and specs to go on. I really have no knowledge of how to design or tune a port, which is why I need advice on this.

[ 03-09-2010, 03:24 PM: Message edited by: thebman ]
Quote 0 0
tekk45
2 cubes, 11.5"x3" port 53 inches long per sub. This box will get low and be loud with modest power.

Quote 0 0
tekk45
Make sure all the corners are rounded in the port.
Quote 0 0
thebman
is that size including the port space or not? 2 cubes and all that port would require a HUGE box, and I simply dont have that much space to work with. Also, is there really any reason that I cant make a single port for both subs? I dont see why this would be a problem.

I have actually just built a ported box for these subs, and im hoping its appropriate. It is a 38x14x19 box, single chamber, single port. Port opening is a slot style, 12.5" by 3.5", rounded exit and rounded inside edges, with a length of 27 or so inches, cant remember exactly, basically I went 14" in, and 6" around the back side of the box with the port.

The port is located along the side of the box, which effectively creates a longer port because of the side wall. After all is said and done and taking sub displacement into account, I should be tuned around 31Hz or so. Does this design sound reasonable for my application?
Quote 0 0
bradb01
what type of vehicle are the subs going in
Quote 0 0
bradb01
go with a three inch pvc port about 6inches long for each sub and do a 2 and a half cubic foot inside airspace box
Quote 0 0
bradb01
i built the same box for my boy with the same subs i pac manned the box and ran seperate ports it dropped about a 36hz low note but still caught all the notes up to 60hz
Quote 0 0
thebman
im saying that I already built the box... you still havent answered my question
Quote 0 0
patotay
how about a horn?
Quote 0 0
Contact Us | Legal Notices | Privacy