im thinking of building a sealed box for my 12" alpine type r, i have a ported which isnt bad, but ive been hearing that the sub doesnt do very well in a sealed box any one have and tips or thoughts

 

I will draw a enclosure for you

 

Make an enclosure using these dimensions and you will create a 1 cubic foot sealed enclosure:

Top = 18"x10"
Bottom = 18"x10"
Front = 18"x13.5"
Back = 18"x13.5"
L Side = 8.5"x13.5"
R Side = 8.5"x13.5"

 

I prefer a sealed cabinet as I find the bass response much tighter, and clearer. many like the extra output from a ported cabinet.
Keep in mind you will need to put some insulation in the cabinet preferably Dakron.

 

thanks jalat. so itll be 1 cubes at how many hz??

 

Personally I prefer sealed enclosures. Then again I'm a fan of 15" subs as well. I find that if you can get a well porportioned sealed enclosure for a sub, it will sound a bit better than a ported enclosure. It will have a bit of a tighter bass, but any of my friends can tell you that you can still hit low notes pretty damn well. Because of the air compression and expansion it's also a bit easier on the woofer.

Ported boxes are great too if you know how to do them. They do (can) give you a bit more volume and a bit more low bass. The problem however is when you listen to music that doesn't like your box. If the frequency starts dipping below the F3 point, then you can really, really do some damage to your subs as they go free air. (I've seen it happen and it ain't pretty.)

 

thanks ken for the info, do you have any specs or help for a 12" alpine type r?

 

N/A for a sealed box. You can't "tune" a sealed box - you can only tune a ported or a bandpass.

 

ohh haha alright that would make sense.

 

Alpine suggests a .7 cuft to 1 cuft sealed enclosure. You're looking at .071 cuft displacement, so you're looking at a box that will (without the sub) be about 1.7 cubic feet internally. If you want the bass to be lower anyway, I'd stick with 1 cubic foot as it'll allow woofer movement to be a bit more loose. I don't have the time this morning to draw up specs for it, but that part isn't that hard anyway.