I am building a sub enclosure using plans from TGO. I have dual 10" subs and each calls for a 4" diameter by 12" long port. The enclosure height is only about 13". Is it okay to have the port pipe just an inch off the bottom. I could try slanting it but that makes the hole harder to drill. I could raise the pipe up 3/4" out the top and make a bezel for it which would be easier than angling it. Would it lose a lot of sound if I made the pipe just 10"?

Any help would be appreciated. Thanks.

 

Unfortunately this is NOT the best site for intelligent audio responses. I would recommend you check out one of the many audio forums.

With that said, the port dimensions depend highly on the specification for your subs, your intended power, and your preferred tuning frequency. I highly doubt you need a 4" port for a 10" sub. What sub and amp are you using?

 

All Polk Audio. I have the PA660 amp for the speakers and the monoblock PA880 for the subs. The subs are the Polk DXI 10s.

This shows port diameter and length under the details tab.

http://www.crutchfield.com/p_107DXI1...65#details-tab

 

Port diameter is highly dependent on intended input power. And the port length is highly dependent on box volume, port diameter, and tuning frequency. Based on the link, you can only assume that those port dimensions are for the recommended ported box size of 1.25 ft^3. Is that how big your box will be? I also see that it does not list a tuning frequency. If you are really set on building a ported box, you need to either follow their dimensions exactly or model your own box. There is free software out there to do this, like WinISD.

http://www.linearteam.dk/default.aspx?pageid=winisd

A 1" gap between the end of the port and the box floor is probably a bit tight, but I don't think you will have any problems with it. You can always put a bend in the port. That is what I would do.

 

Well the box is actually 2.075 cubic ft, which I split in half so each box is ~1.0375. So it is under the recommended size but larger than the sealed size. Am I better off not to port it?

Edit: I could build a 1'x1'x3" tall extension into the top of the box for each to get to the 1.25 cf if that would be better because I haven't built the top yet.

 

So its 1.04 ft^3 - speaker volume - port volume = 1.04 - ~0.05 - 0.087 ~= 0.9 ft ^3. If you cannot match the recomended volume, then your tuning is going to be off with that sized port. Most likely the tuning will be at a higher frequency. You really need to do the analysis to get it right. Sealed is fine, and its what I like for music, but you get less volume per watt.

 

I don't need a tremendous amount of volume. I just want good sound. Seems like sealing the box will be easier and better. Thanks for all your help.

 

Sounds good. Good luck.