Arrogant

Ok, so I am going to have a custom installation done within the next two weeks for my trunk, and here is my delimna. I was told, and have heard on here that it is hard to movae air from the trunk of the sedan to the cabin. I have already removed the factory sub so I can let some air move in between the trunk and the cabin. However, the installation place is stating in order to get maximum air flow I should face the subs towards the cabin, seal off the box from the trunk, and port the box through the hole where the factory sub is. Obviously sealing off the trunk involves a lot more money than just building a rear facing sub setup (literally its like 800 more). My question to you guys is do you think this is really needed? Really the options I have are as follows, and all I am really looking for is maximum bass.

1 Forward facing 12w6 with enclosure ported directly into cabin
1 Forward facing 10w7 with enclosure ported directly into cabin
2 rear facing 12w3 (cheapest)
1 12w6 rear facing (third cheapest)
1 10w7 rear facing (second cheapest)

Any ideas? Again, only looking for maximum bass for the money, and at this point I am only goig with JL so please no other recomendations.

Neddy_G37

This is an easy one, as I was in SPL competitions a few years ago. You are limiting yourself to ported or sealed enclosures. Keep in mind that bass is omnidirectional. No matter where the sub faces, your going to feel and hear it in the cabin. My suggestion is to go with a bandpass enclosure and use the 12W6 sub. This tutorial will help explain things a little better.

JL Audio » header » Support » Tutorials » Tutorial: Bandpass Enclosure Characteristics

However, there are 7 types of bandpass enclosures and depending on budget and complexity of the box design, you can get some serious, windshield cracking, stomach aching bass out of a single 10 inch sub. But it takes a LOT of power!!

Arrogant

Yes, I actually think bandpass is what I might run with, but 12W7 is not in the running due to price. Any opinion on 2 12w3 vs 1 10w7? Both gettin 1000W? I am leaning towards the 12w3's.

Neddy_G37

Depends on your budget really. I have seen an MTX Blue Thunder 10" crack a windshield in a 7th order dual reflex box no bigger than a suitcase. That sub was only $65 at the time. I suggest getting a sub that can handle the pressure of a bandpass enclosure, preferably dual voice coil, and get a clean, low THD amplifier to run it. 1000W at 1% THD will not be as powerful or clean sounding as a 200W amplifier at .008% THD. However, assuming all things are in order, I see no problem with running a 10 or 12" sub. Speaker choice depends on budget, box choice depends on your designer.

Neddy_G37

This is a great example of a 4th order bandpass that utilizes one sub, takes a ton of power to operate efficiently, but can be made to work in a tight space with a small sub sounding much larger!

Absinthe

Your installer is essentially on the right path isolating the trunk from the passenger compartment. The theory is that you will have the direct radiation coming from the sub towards the front of the car and a reflected portion of the bass coming from the trunk. These waves will arrive at your ear at different times and in a worst case can cause your base to fade in and out. Take into consideration that this type of install is usually only undertaken on competition systems. My first install on my G had the subs mounted facing forward right behind the rear seats and the trunk was pretty well sealed off. It did provide strong bass even using a sealed enclosure (129db's). The drawback was the constant distortion I was getting from the resonance of the cabin and the bass lost a lot of control and tightness in efforts to get more volume. The bass became even more imprecise when I ported the enclosure. Since then I've settled on sealed enclosures on both sides of the trunk (aimed rearward) which helps with the out of phase direct and reflected waves. I lost about 4db's of sound but gained a world of improvement in the overall quality of the system.

I don't have any good numbers for subs in 6th or 8th order enclosures since I didn't want to devote that much space to speakers but I did do a 6th order setup in a Camaro back in the late 80's that hit in the mid 135 db's that was pretty manageable. Ive also done multi order subs for home use and they do fairly well on systems that utilize smaller bookshelf speakers; but they are a P.I.T.A. to build! Additionally, you need to be damned careful that you don't allow the sub to operate out of its tightly defined parameters determined by the enclosure. Excessive operation below the port frequency will cause the sub to unload and destruction will happen quickly after that. Another thing to consider is the transient response of sixth and eighth order enclosures are horrible. What this means to your ear is your bass, while loud, will be imprecise and muddled. Because of these issues I cannot recommend anything over 4th order for automotive use.

If you do go with a multi order enclosure, Id love to see pics and get your impression on the sound accuracy and SPL level.

Arrogant

Hey, thanks man, so it sounds like in your opinion for the average joe who wants loud bass but is not competing spending money sealing the trunk and firing forward is a waste.

Neddy_G37

Yes, it is a waste. However, some Dynamat in the right places that are prone to vibration will do wonders.

Dynamat.com | Dynamat Car Audio Products

Absinthe

It is in my opinion plus its a lot of work!

Like Neddy suggested, dynamat the trunk in high vibration areas to help keep the resonances at bay. Its the little things like the tail lights, and the emergency trunk release cable package shelf, and any loose wire bundles behind the trunk liners that will positively annoy you. Theres a product called Overkill made by Second Skin Audio that works great although any sheet closed cell foam will work too

Second Skin Audio

Arrogant

Welp, was just at the place today and decided to go rear facing basically because of cost, it was 1000 less to go rear facing. However, they had insane deals, so I decided to go with the 13.5W3 instead of the 12W3 the 13.5W3 were only 165 each, insane deal so I had to take them. Install is set for next tuesday. Only question now is if I want to go ported. I have always had ported, and like it, but if i go ported on this car i lose the spare tire access. I think since I have triple A I am fine with that. Something I am going to have to think about over the weekend. Really excited over this, then I can move onto rims / tires, and then brakes.

Neddy_G37

While I am happy your getting the work done, and am sure you will be happy in the end, help me out here. What are you having this shop do, as far as your enclosure goes, to where changing the location of the holes costs $1000 less?!?!?! Is this for just a single speaker enclosure?

Sealed enclosures produce a tight, firm, controlled bass hit.
Ported enclosures produce a "boomy" type of bass
Bandpass does both.

Arrogant

So, there were other things besides the work that caused it to be 1000 less. Basically that 1000 difference was a single 10w7 instead of 2 13.5w3's. It was for firing a single sub sidewards and completely sealing off and dynamating the trunk as well. It was actually more like a 900 dollar difference. I have already removed the factory sub so hopefully that is enough to get some of the air moving into the cabin. I really like the sound of a sealed off trunk with forward facing subs, but the cost was just too much at the end. Getting some trim work done for the amp as well. Right now everything is going to be covered in basic black carpet, but I might change out the finishing in another 6 months to viynl or something.

I really think I am going to say screw the trunk space and go for ported.

G37Xtreme

For me, I couldn't care less about access to the spare. I'll use roadside rescue if needed. But trunk space is crucial, so anything large enough to block spare access is a no-go for me. I too am thinking about adding some boom...but my solution would be much smaller, and simpler.


I am thinking something all-in-one at this stage. Basslink or Bazooka Tube....


This could all change as I do more research and get inspired.

Arrogant

Ok, so help me out with something else guys. Assuming I go with the ported enclosure and have a false wall to create a factory look would I not be trapping the air in the area between the wall and the back of the trunk and the lid of the trunk? If the hardest part is getting air into the cabin then doesn't building a false wall hamper that, or does it even matter? I a guessing this might be different if I go with sealed because the box will be smaller, thus making the wall closer to the rear of the trunk and then air could easily travel through the factory subwoofer hole.

Neddy_G37

Keep in mind, bass waves will travel through wood, carpet, metal, etc. So unless your going to seal the trunk with concrete or lead, the sound will come through unhampered. The decision to go with sealed or ported has nothing to do with how far the waves will travel but has EVERYTHING to do with the music you listen to and how the box is expected to reproduce such sounds. Classical requires a firm hit from sealed, rap music requires a boom from a ported.