Wagon Box?

[TheBetterMethod]

I've got to build a box for my '05 Subaru Outback Wagon.

I've got the sub from my last car, but I'm starting with a clean slate for the box. So I have a few questions.

But first I'll give some background.

The sub is a Fi Q 15. The box will be ported and tuned no higher than 33hz. I'm not sure exactly what the tuning will be yet.

The volume of the box will be about 4cu.ft. after sub displacement, and the port will be one 6in. aeroport, all external.

I'm going to use 3/4in. birch ply for the enclosure to save a little weight over mdf.

The sub is going to be on the driver's side pointed up at the roof, and the port will be on the passenger side, pointed back toward the hatch.

So the questions...

I know there's a rule about not putting the exit of the port too close to the hatch, but it seems like there are a lot of different opinions about what too close is.

I think I'll have about 3in. between the exit of the port and the hatch. Does that sound alright?

Next thing is, I plan on adding 45˚s in the 4 vertical corners of the box. Is there a rule for how big the 45˚ should be?

[412 CVX]

i usually do my 45's 3 inches wide or 4 and a quarter inches wide. all depends on how much air you want to displace.

3 inches should be plenty from the back hatch. my rule of thumb is as long as it's at least half the port width. but hell it's different with every situation

[TheBetterMethod]

Cool, I was planning on 3in. for the 45˚s anyway. Thanks for your input!

I'm gonna be building this in the next week or so. So if anyone else has input, I'm all ears.

[john253a]

first things first

port is too small, a single 6" is only 7:1 ratio you want between 9&13:1 for aero, 12&16:1 slot

so youll need

2x6" @ 33" long (14.1:1)

or

or 4x4" @33"long external for a 4cuft net box (12.6:1)

witch ever size you chose youll need that much in front of port,

there are a few options put some of port inside box to shorted it up on outside

or build the entire port inside the box

something like this would be ideal if you can fit

Edited April 4, 2012 by john253a

[412 CVX]

that post was a lot more confusing than it was helpful...

single 6" aero in 4 cubes would give you about 7 sq inches per cube of port area.

you would wanna strive for more port area if possible, but if you ended up doing the single 6" it would work. especially if it's flared.

[SnowDrifter]

How much power are you running? That will effect how much port area you need.

At a glance, it seems fine with how you described.

[Nikitaaa]

In my Subaru Outback, the box was much louder to the ear when scooted back as far as possible. Fortunately for you you're just running a one sub set up so you can play with box positioning and distance from port to hatch.

Mine AQ is probably 6-8 inches away.

[n8ball2013]

you are going to have to play with it to decide teh optimal distance. good rule of thumb is to keep it away from the trunk the width of the port. of course thats not bulletproof either.

[Mtnbikecrazy55]

In my wagon, I have sub back port to passenger side with the box all the way up against the the drivers side. About 10 inches of space in front if the port.

Sounds good

[TheBetterMethod]

Alright, thanks for the replies.

I'm running into some restrictions. My box can only be 13in. tall and 40.5in. wide. Those dimensions are pretty well set in stone, if I want to use an external port. Which I do. And if I use the external port I have a length limitation of about 36in. and at that length the port would be basically touching the hatch and the front of the box would be against the back of the seat. I really don't have room for 2 6in. ports and definitely won't be using 4 4in. ports. So I'm back to the single 6in. port. And I know the ratio is about 7:1, but I don't think that's going to be a big deal. I might be wrong on that, but I'm willing to give it a shot. If it doesn't work out I'm ready to chop, cut and rebuild. The way I've got it figured is 3.8cu.ft. after all displacement. And a port about 15in. long. for tuning around 32hz.

I don't want to do a slot port, because of the inability to adjust after they're built, and the extra work of building one.

BTW, I'm powering it with 1200 watts. Might upgrade to 1500 if I see a need.

Thanks again for all the input.

Edited April 4, 2012 by TheBetterMethod