2nd gen double cab running a single 12" sub behind seat?stealth

2 12s would bang

 

Thanks for adding nothing useful to this thread. We were almost to a point where we were getting somewhere.

 

Ok, I ran the 10" through UniBox to confirm everything you guys have already done and I am coming up with the same results as you for the 4" port with a great response curve and low port noise but it would require a 51" port.

At a 3" port size it only needs to be 28" as mattg said, but at that size there could potentially be a lot of port noise. Here's the graphs using a 3inch port.





I have never built any boxes with anything other than a straight port. When you say I could wrap the port around the motor, how would the shape/angles of the port affect the response? I have never built a box like that, seems more like a transmission line box than a vented box but I dont have that much experience.

Thank you both for all the help so far. A little planning goes a real long way, no?

 

If you use a PVC pipe, just measure the outside and inside of the bend, average it, and us that as your length.

If you do a "slot" port, same thing - use the middle or average length of the bend.

As to port noise, check out this build log:
http://www.mobilesoundscience.com/f14/chads-2004-civic-si-64/

I think he did something like a 2.5" square port, so less port area than a 3" pipe.

Also, you can flare it to get rid of some noise.

 

Port noise is dependent on excursion.
Excursion is dependent on power.
Power on Chad's JL 500/5 was only 250watts.

Try modeling the sub again with only 250. I bet it looks fine and dandy with a 3" port.

 

Good call, forgot he was running that amp...

 

Since you were curious about this I ran it at 250W and it still shows some noise but its a lot more acceptable than at 450W. I am doing some modeling in SketchUp to see if I can have a long slotted port wrapped around the box which fits behind the passenger back seat as discussed. I'll post shots of the model once I have it.

 

Like I said, it it's behind the passenger side it will be a cake walk.

 

I modeled a 20 liter box that I believe would fit behind the seat. It's a trapezoid with 8" and 1" bases and 19" and 20" sides. The vent dimensions are 3"x3" square with port length 36". The actual wrapped vent design extends about 16" out from the box. Those slots you see in the wireframe view in the back of the enclosure are for the child restraint hooks. I will just put small pieces of 3/4 mdf over them inside the box but didnt put those in the model. Any comments or criticism on the design is welcome.

I still need to design some kind of amp rack that will work around the ridiculous vent. I think the nine.1 will fit mounted right over the vent running lengthwise. That should also leave enough space for another amp for the fronts and for the crossovers.

There may be enough room to also put a fascia over the entire back as well to cover the exposed top area and hold a grill for the sub.

My real issue is that I dont have a table saw or router and dont really want to buy just for this project. In the past I have borrowed but for some reason I cant think of anyone now that I could ask. I might try looking around for a local shop that could assist.

 

The design looks good, but...

1. you didnt slot it for the rail across the back, which may be the biggest problem, height wise.
2. Along those lines, 8" is a max external dimension, IIRC. If that is the case, you would have to under mount the sub, or do a "flush" mount probably 1.25" or more deep, for surround + excursion

3. If you are using the passenger side, why not build the box the same dimensions all the way a cross, and do the port inside. It wont add a tone of space, but what airspace you can get "above" the port in the drawing will lower the length needed, and look cleaner.

If you plan on mounting the amp above that, its a different story...

 

Very solid design. Take heed of Matt's thoughts and double check those things.

Only thing I'd add is move the woofer to the far left of the box as far from the port as possible.

 

And if you can't find a builder let me know.

 

I haven't read much of this thread but you should check out Supercrewsound.com they have very nice boxes and great customer service backing them. I've bought 3 boxes from them they all have arrived in a timely manner about 2 weeks very good quality boxes that you can run some decent subs in. I haven't heard much of anything good about Taco Tunes. From what I've read and seen Mr. Marv does good work he has custom made boxes for the storage compartments under the rear seats but it's a good bit of work and know how to do this. Good luck. My advice is to spend the big money doing it right the first time do a little bit of research and get what you want.

 

Thanks Matt, thats definitely something I need to consider. I need to go back to the drawing board again because you're right, the sub will slap if I dont recess the mount more, and at that point I am running out of mounting depth because of the trapezoidal shape and angle. I thought I could get away with not slotting the box but I will need all the space I can get to get to the necessary enclosure volume and mounting depth.

After looking closer at Mr Marv's boxes, I really want to do one like he makes with the recessed cavities for the brackets. At this point I am going to wait til his site gets back up and running to check out what his premade options and costs are.

Ultimately I'd like to get something with a similar, flat frequency response as shown in the plots and I had heard so much good things about the Dayton HO that I wanted to use it. But as I have not purchased the sub yet I could still go with another option.

 

I wouldn't worry man. Response still looks good in a 15L box tuned to 30hz. Your port will be longer but I think you should be able to do it. Do what you need to do to get the depth you need and just don't go too much lower than 15L. Try and keep tuning around 30. Use some polyfill inside the box and it should lower your tuning a little.