Size box for sub?
 

Need to make a custom box for a 12 inch sub, how big should it be? Ported or not? Thanks

see response in general section

Thanks

12" x 12" x 12", basicly 1cu foot

varies on the sub. get the sub make and model number and get ahold of the builder.

Exactly.

Look up the sub online and find out the specs. It should give the proper cubic feet needed.

You are looking for the Thiele-Small (TS) parameters, and then match a box accordingly. A few tips: A ported box will give slightly higher output than a sealed box, a ported box is harder to tune correctly, a sealed box can be smaller and be EQ'ed to give better frequency response, the smaller the box-the higher the tuning frequency. Most driver websites will give suggest box size depending on your requirements. What driver do you have in mind?

The sub is a Hifonics and the amp is a JL audio 500. Don't really need it to thump but want a nice clean and deep bass.

Depending on which Hifonics driver it is:
Sealed design, go with no les than 1 cubic ft and no greater than 1.5 cf. Smaller box is tuned higher (around 45hz) more boom but less deep bass extension. Larger box is tuned around 38hz, little less output but deeper extension. You get the tradoffs. Either box should be stuffed.
Ported design, a little tougher to spec out but would be safe with 1.75cf to 2.25cf box. Port size should be tuned aound 33hz to 38hz. Hope this was helpful.
JL 500 amp is a good amp. I believe it also has an adjustable eg with frequency and slope adjustments.

Thanks for the info, know the direction to go now, Thanks

Dont build a 12x12x12 box. remember to calc based on internal volume. also use 3/4 " wood. not 1/2" make sure to glue and screw the box and caulk it too.

i have a box with 2 alpine subs they are 10 inch you can have for 125 plus shipping i paided over 500

The simple solution is to just use the engine compartment as an infinite baffle. Unless you're really trying to make super low frequency bass, an infinite baffle enclosure is really efficient and doesn't take up any space on the boat or add unessesary mass. And no, the engine compartment does not have to be sealed for it to work right, the distance from the front of the sub around to the back just needs to be longer than the wavelength of the lowest frequency you are trying to reproduce. Not really that hard given most music you're going to listen to on a boat doesn't really need super low frequecies (20hz), just a lot of 40hz and above.

Exactly A sealed box will be different then a ported box with the same giving speaker, sizes will change on box area based on the make model sub ya have.. :)

John jr