Yes, you should honestly give a Image Dynamics Q sub a try I think you will be pleased.

They are awesome but they are very specific application and they do not behave in a way a typical subwoofer does. They work best when boundary loaded and you need a minimum of .8 cu ft, no less! They are very very tight and they need a lot a power.

here is my boundary loaded subwoofer enclosure. Notice from the pic's that the sub vents ato the very back of the cabin of the car. the subwoofer is also angled slightly so it will focus bass energy like horn loaded enclosure.

Inside the enclosure and amp rack its back lit with some small blue led lights to showcase the driver and the 900/5 JL amp.

This sub hit unbeliviebly hard and tight!! I wouldnt trade this sub for anything else! My ears are still hurting from this morning when I was fine tuning it.

Plus its totally stealth!! The only visable car audio upgrade inside my car is my head unit.

That will still lose his spare tire which he wants to keep. Still looks good.

Your right, but this reply was more for answering "huff442"'s question about the 13TW5 and what it can do.

I disagree about the statement SQ stops at 12 inches. My experience has been that 13.5" subs sound every bit as good as 12's if not better.

Anything larger is a compromise. I havent heard very many 15" subs that sounded tight. I can think of only one instance. I listend to a Rockford Fosgate Demo vehicle with (4) 15" subs and it was sonic perfection but they must had over 50K in the vehicle.

I know a lot of people think JL Audio is overpriced and overrated but they have more engineering, innovation, and patents than anyone else out there. I have never owned a JL audio subwoofer that I wasnt impressed with and I have had many!! They make a damn good subs and amps. yes they are expensive but I know I will be happy with the equipment which is more than I can say for some others I have tried.

Well I have to disagree with your disagreement. Anything over a 12 inch sub becomes sloppy and it not able to reproduce tight acurate bass such as a 8 a 10 or 12.

Anyone tried the Z Enclosure Upfire boxes?

Nissan 370Z UPFIRE Subwoofer Enclosure

I prefer the look of this one over the rear facing. This is my first car without an enclosed trunk, and I'm not too knowledgeable regarding car audio, so I have no point of reference for how/if an upfire would effect sound quality in a hatch. Previous cars have all been single or dual ported 10 or 12"s.

For the Z I just want to add some nice depth with good tight sound reproduction. Not needing to win any competitions, but would like my Z to sound at least as good as my MazdaSpeed (Kenwood Excelons all around and ported 10" in the trunk) Leaning toward the Upfire with dual 8"s.

A up firing box is alright but the sound will be fired right back down towards the sub. You would get better sound with the sub facing the rear.

Without further argument on that subject, I have said this before and I will say it again. Sound quality is very subjective.

Here is a perfect example, some people swear by 10" subs, personally I have never been happy with a 10" sub and always find myself upgrading to a 12 and recently I have been playing with 13's and I think they are the shiznick!

This is off topic big time, but I will say it anyway to reinforce my point.

I have a home theater sub with an 18" driver in it and it hits tighter than any 8, 10, or 12 I have ever heard. In fact its the Home Theater sub that all others are measured by, at least at the time I bought it. Granted it has a 3000watt amp and cost a few grand, but its an example that very large sub drivers can have the SQ that rivals smaller ones.

Be careful when you generalize as there are always exceptions to the rule.

I agree with Matt on this! Rear firing for sure. It gives you much better TF. Dual 8"s would sound great too.

Agree to disagree.

No problem Matt, i am not trying to put down your opinion in anyway. I just dont like it when people generalize. People who generalize are usually ignorant. You are not ignorant and are clearly an intelligent person who knows a lot about this subject.

Thank you you seem to know a bit yourself as well.

Question for 2fast4thelaw. Your subwoofer enclosure design intrigues me. I'm not familiar with the boundary loaded concept in a car sub. Is this similar in design to the super high output PA systems? Regardless, how did you determine the volume of the chamber in front of the speaker? What about the size off the slot opening?

The design is heavily influenced by High Output PA speaker design. The driver is angled slightly to horn load it to disperse bass energy. I will give a little tutorial on Boundary loading and Transfer Function and how they relate.

First off everyone knows that a subwoofer placed in a corner increases its output. This is because it has more boundaries to bounce off from. The more boundaries you can create, the more bass energy can be generated. In my enclosure the sub fires directly into the floor of the vehicle and bass is forces through a small chamber with a large vent at the very rear of the car. In a since this is a bandpass enclosure but the front chamber is not calculated to produce a specific frequency.

Transfer Function is maximizing the length of your bass wave from the subwoofer to you. In my enclosure the bass wave hits the very back of the car and bounces off of the rear window which then reflects it to the windshield which then reflects back to you.

Also Matt (BigAudioFanat) pointed out something I didn’t even think of. The downfireing driver transmits energy through the floor of the car so you get a lot of tactile feel. I feel this sub more than I can hear it. It feels like its right under my seat.

Here is a good link to illustrate what I am talking about.

Measuring Transfer Function, Boundary Loading & Soundwaves

Very interesting. Do the smaller boxes on either side of the speaker chamber add a significant amount of volume to the total enclosure volume?

How long till we see these enclosures (or at least plans) for sale? This could tempt me to lose the spare and buy run-flats.