Port question

[gilhaven]

Ive built an enclosure (2.4 cuft) and want to tune it to 35Hz with a round 3" port. Ive used a website that tells me i need to make it 4.28" in length. My question is that I'm using 2 alpine sws10d4's....would that mean I'd need to use 2 ports? Or, would one port that's 4.28" long give me the same sound as 2 ports, each being 10.78" long? (Again...data taken off the same website which I cant link the url due to this being a new post) Thanks in advance. It'd be good to get some clarification before I start cutting holes.

Click to read more...

 

[SounDrive Pro Seller]

Ive built an enclosure (2.4 cuft) and want to tune it to 35Hz with a round 3" port. Ive used a website that tells me i need to make it 4.28" in length. My question is that I'm using 2 alpine sws10d4's....would that mean I'd need to use 2 ports? Or, would one port that's 4.28" long give me the same sound as 2 ports, each being 10.78" long? (Again...data taken off the same website which I cant link the url due to this being a new post) Thanks in advance. It'd be good to get some clarification before I start cutting holes.

One 3" port is not enough port area for you. For a box that size, you'll want at least 2 4" ports or 3 3" ports. The problem you run into is that if you're going to use 3 3" ports, you'll need about 20" of port length to get 35Hz tuning after accounting for sub displacement

^To explain that - for aero ports you want to have 9-13 square inches of port opening per cubic foot of your enclosure. 3 3" ports would give you a ratio of 10.9 sq in per cube. If you have less than that, you'll be choking your subs and not getting their full output