Roughly 16 cubes available

[mat3833 10+ year member]

I'm trying to decide between running 2-15's, a single 18, or a pair of 18's. I'll be having top assemblies built soonish for the Neo radial Beehive motors I have. This will either be a trunk enclosure "blow through" using the cargo pass through(21x34 opening) or a back seat enclosure port through the rear deck so I can keep my trunk space for tools. I suppose I could also split the difference and put part of the enclosure in the rear seat area and part in the trunk.

Completely using the trunk space nets 17 cubes flush to the cargo opening, but a more realistic size would be 15 cubes or so.

Back seat area to the top of the rear deck is about 28 inches, Door to door is 53 inches, and front to back is 23 inches at least so roughly the same, but I can go taller potentially.

Ive always been fond of infinite baffle setups, so I'm thinking a very large sealed enclosure would be more to my liking, but a low tuned ported loading off the rear glass would probably be sick.

My goal for this build is a good daily system that sounds good and can be brutal if turned up. I listen to everything from Sabaton to Wild cherry to eminem. One of my favorite past times is dropping some "bass I love you" on unsuspecting co-workers. Cone area is king keeps popping into my head, but if I go with the 18's I'm limiting my enclosure options simply due to sub size and space requirements. I have a Smart 3k for power, and if I remember correctly the top assemblies will be D2 so 2 ohm final load at the amp.

Matt

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[mat3833 10+ year member]

I realized that I didn't include any details about the vehicle.

The car is a 2004 Jetta. Trunk has been sealed off from the passenger compartment except for the pass through opening. Sound deadening and CCF throughout the car and the rear deck has been reinforced. Ideally a back seat enclosure is best since I carry a good bit of tools to and from work in my trunk. I'm leaning towards the pair of 18's simply because it's possible, but if anyone has experience with a back seat enclosure like this I would love to hear your suggestions.

Matt

 

[LsGuy]

Sound deadening is great, but for this setup may want to look into frame reinforcement lmao

 

[mat3833 10+ year member]

Sound deadening is great, but for this setup may want to look into frame reinforcement lmao

It's a unibody, lol. And I'm not interested in metering 155 or anything. Yes, it will certainly be loud, but it can be turned down for daily listening. Yes, I could probably throw 2k at each and destroy things. This is more or less a final evolution of slowly adding more and more cone area seeking some kind of "perfect". If it doesn't work, I may ******* wall it or something, who knows?

Matt

 

[Firewalker]

Talk to buck he has done designs for that sort of vehicle and doesn't charge much for what he does.

 

[mat3833 10+ year member]

Talk to buck he has done designs for that sort of vehicle and doesn't charge much for what he does.

Buck is going to be designing whatever I pick. Unless he somehow decides not too, lol. I was going to have a 12 built to put a horn in the trunk just for fun. I need to get some cabin gain measurements and whatnot for him.

I'm just having an open discussion where people who have done anything similar can toss out their opinions. Im horribly indecisive, and hearing other people's thoughts and experiences will hopefully help me.

Matt

 

[metalheadjoe 10+ year member]

If you did a backseat enclosure, would you remove the back seats? Could you haul your tools in the back seat instead of the trunk? That would make more sense, since you can move tools, whereas the subs are a more permanent accessory. I much prefer things to look as clean as possible.

 

[mat3833 10+ year member]

If you did a backseat enclosure, would you remove the back seats? Could you haul your tools in the back seat instead of the trunk? That would make more sense, since you can move tools, whereas the subs are a more permanent accessory. I much prefer things to look as clean as possible.

The back seats are already out of the car. I'm comming from an infinite baffle settup.



I could keep tools in the backseat instead of the trunk. That's why I have both options. The main issue with doing a trunk enclosure is the pass through. It's alot smaller than the rest of the trunk, and on top of that any tools I have in the back seat area would be able to slide into the comes or into the port. Looks are kinda secondary at this point, function over form all the way here. I have a second vehicle to haul the kids and get groceries.

Matt

 

[mat3833 10+ year member]

@Buck

Thoights? I'm working on getting the transfer function of my jetta recorded, and I'm going to get some more accurate measurements of both the trunk and back seat this weekend some time.

Matt

 

[hispls 5,000+ posts]

Where did you find coils to fit those NRT motors?

I would suggest that you'll get best results if you just do a flat wall, you will maximize volume, solve a lot of potential standing wave issues you'd get from some odd shapes/angles in the rear, and simplify your options for modifying tuning after it's all up.

I can't imagine you'll really have 16 cube net in a small sedan after building box to adequate thickness and counting out displacement of an adequate port. You may consider actually building the shell of the box then plan to put up the baffle last after you can get some measurements of how much space you actually wind up with and then planning cone and port area from there based on how much volume you have and how well whatever it is you plan will line up on the baffle.

You may do fine with a large sealed box provided the specs of your subs work out for that alignment, dunno how you'll figure it out unless you have sourced OEM softparts and can find old published specs.

 

[mat3833 10+ year member]

Where did you find coils to fit those NRT motors?

I would suggest that you'll get best results if you just do a flat wall, you will maximize volume, solve a lot of potential standing wave issues you'd get from some odd shapes/angles in the rear, and simplify your options for modifying tuning after it's all up.

I can't imagine you'll really have 16 cube net in a small sedan after building box to adequate thickness and counting out displacement of an adequate port. You may consider actually building the shell of the box then plan to put up the baffle last after you can get some measurements of how much space you actually wind up with and then planning cone and port area from there based on how much volume you have and how well whatever it is you plan will line up on the baffle.

You may do fine with a large sealed box provided the specs of your subs work out for that alignment, dunno how you'll figure it out unless you have sourced OEM softparts and can find old published specs.

Don has 3 coils that fit the gap. They are a bit taller wind width so they might not work, but if thats the case I'm having coils made.

As far as volume available, I did some quick measuring and this is what I've got leaving some wiggle room

52 wide at the front and 49 wide at the rear at the top.
51 wide at the front and 47 wide at the rear on the bottom.

26 deep at the top and 28 deep at the bottom.

22 tall in the front and 24 tall at the rear.

Split the difference on the measurements and minus 15 percent for odd shapes and I've got 16 cubes in the backseat. I can pretty easily get more space by going taller or deeper.

I'll be getting some angle measurements and doing some proper volume calculations this weekend.

Ive consided walling it, but this is a daily build and a wall is a bit above my experience level. I still drive my car to work, pop out to Daytona and hang out with friends, etc. I could probably manage to wall it properly, and I'm sure it would be awesome. But I'm more interested in a backseat or trunk build.

As far as tuning, that's why I like the idea of port through the rear deck. Tuning changes can be as simple as building a different port or sealing it up entirely. Volume isn't exactly a concern. This is going to be plenty loud enough for me even if it ends up sealed.

Matt

 

[Buck 5,000+ posts]

@Buck

Thoights? I'm working on getting the transfer function of my jetta recorded, and I'm going to get some more accurate measurements of both the trunk and back seat this weekend some time.

Matt

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[mat3833 10+ year member]

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