ported or sealed?

I would suggest a sealed enclosure with a passive radiator of the same size as your sub. The radiator with have a resonating frequency approximately 1 octave lower than that of the sub. This is all assuming you tune it correctly. Anyway,IMO, a sealed enclosure with a passive radiator gives you a very good conbinatation of SQ and SPL.

It can go on any side of the box that you chose. As the air is sealed inside of the box. So, it's going to expand whereever it can(the passive radiator). I don't think your local car audio shop would have radiators. For some reason, not many people use passive radiators in cars anymore. Makes no sense to me. You can find radiators online. Search google for "Passive-radiators" or "speaker rings". I'll look around for some websites and then post them here.

Here are some sites I found Passive Radiators Explained http://www.speakerrepair.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=10p&Category_Code=AIII+SP

1badnotch wrote: i have one audiobahn aw1051se

Post a link showing the T/S parameters of this sub.  And also, do you have a spec sheet with it, and does the manufacturer recommend any type of enclosure?

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Clarification: A passive radiator speaker system is not sealed, it is vented.  Using a PR can be very tricky as they tend to have very high distortion around the PR resonant frequency, they can create severe phase cancellation problems and thus can make speaker placement very, very critical.  A PR subwoofer can create much more deep bass response than a typical acoustic suspension design with the same driver, but only around the PR resonance.  IMO they are much more difficult to build, to use properly and especially to create acceptable sound quality than almost any other speaker design and should not be attempted by a beginner.  http://www.diysubwoofers.org/prd/Support the12volt.com

Ya, your correct about it being hard to build and Properly tune them. That is probably why not many people use them in car audio systems. The distortion that you mentioned usually comes from the PR over-extending or bottoming out. You can prevent this from happening by using a PR that is larger than the actual driver. I PR system is technically in the class of Bass-reflex (Ported) class, but just think about the way they work. The air inside of them is traped, air neither escapes nor enters the enclosure. The PR supposedly acts as a port by "containing" a constant volume of air.

Just my little note regarding PRs... The way to tell which PR you need is to find one with a swept volume of AT LEAST TWICE the swept volume of the driver you are trying to match it to. Xmax times Sd equals swept volume. A PR enclosure behaves THE SAME as a vented enclosure, except the active driver does not unload as quickly below the tuning of the enclosure, as it does in a straight vented box. This helps protect the driver without subsonic filters and the like. The distortion can be SIGNIFICANTLY lower than the same driver in a sealed box, due to the lower excursion. They also do not suffer from port noise. They are WAY, FAR, MUCH, COMPLETELY (and a lot) harder to build correctly, but if done right, can be truly amazing. My Eclipse Titanium 10 went flat to 18Hz (anechoic) in 2.2 cubic feet. Ya shoulda heard it in my car!!! DAMN!!! Adire Audio makes a hella impressive PR, called the PR15, and I have used it, with extreme success. (Also some fairly spectacular failures LOL). One of those successes was the above mentioned match with the Eclipse Ti. Completely tunable, it is an ideal PR for most drivers up to 12 inches, and even some 15's. Mr. Kephart, is this item still available through Kyle? I think I still want a couple to stack under the bench...It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."