Box design help

[Redford]

Ok, so I measured my trunk today... or well... how much space I'll have to get the box in and out of the car when it's fully built. The dimensions (DepthxHxW)I have to work with are 12x16x40 (3.39 interior cu ft if using 3/4" mdf), 16x16x40 (4.68 cu ft) and 16x17x40 (5 cu ft). There are 3 different measurements for 3 different scenarios of how I want the box built. The first one is if I want the box to fit under the part right behind the fold down seats. The second is if I don't want it to. The third is if I take the the rear speakers out.

Now, here's my main reason for needing help. I am trying to design a box that will be ported and mainly designed for SPL. However, I'd like to be able to hear the sub (DD 9012) without any SQ loss with the seats up (they kind of muffle sound). So I was thinking I could use the speaker holes as area for ports. Someone I talked to about this suggested using round port tubes. I can see why he suggests that as the speaker holes are oval shaped. What I want to know is if I should use 2 ports, one in each speaker hole, or just 1 port? If I only used one, I could put the sub facing upwards underneath the unused speaker hole. Does anyone have any better ideas or suggestions about building this box?

I have the following stats for the sub:
QTS- .28
QES- .29
QMS- 6.2
VAS- 43.0
BL PRODUCT 25TM
SENSITIVITY- 89
FREE AIR 31HZ

I think the recommended ported box size is around 2.5 or 2.75 cu ft.

I can take a picture of my trunk if it helps anyone visualize what I want to do. And I'm planning to get a Hifonics Brutus 1500 amp for it once I sell my old system.

[Alaxan]

Ok, so I measured my trunk today... or well... how much space I'll have to get the box in and out of the car when it's fully built. The dimensions (DepthxHxW)I have to work with are 12x16x40 (3.39 interior cu ft if using 3/4" mdf), 16x16x40 (4.68 cu ft) and 16x17x40 (5 cu ft). There are 3 different measurements for 3 different scenarios of how I want the box built. The first one is if I want the box to fit under the part right behind the fold down seats. The second is if I don't want it to. The third is if I take the the rear speakers out.

Now, here's my main reason for needing help. I am trying to design a box that will be ported and mainly designed for SPL. However, I'd like to be able to hear the sub (DD 9012) without any SQ loss with the seats up (they kind of muffle sound). So I was thinking I could use the speaker holes as area for ports. Someone I talked to about this suggested using round port tubes. I can see why he suggests that as the speaker holes are oval shaped. What I want to know is if I should use 2 ports, one in each speaker hole, or just 1 port? If I only used one, I could put the sub facing upwards underneath the unused speaker hole. Does anyone have any better ideas or suggestions about building this box?

I have the following stats for the sub:
QTS- .28
QES- .29
QMS- 6.2
VAS- 43.0
BL PRODUCT 25TM
SENSITIVITY- 89
FREE AIR 31HZ

I think the recommended ported box size is around 2.5 or 2.75 cu ft.

I can take a picture of my trunk if it helps anyone visualize what I want to do. And I'm planning to get a Hifonics Brutus 1500 amp for it once I sell my old system.

What kind of car is it? What kind of space do you have directly under the rear dash panel? Are your trunk hinges potentials to get in the way? You can do an oval or round port, but if you have it totally clear under the dash. I have taken before and run a slotted port up thru the dash. Keep in mind when using a port that extends OUT of the enclosure that space outside is not included in the port dimensions. Pointing the sub up is not a bad idea, but not always the recommended if it will be under an open hole. So long as there is still a screen over it to keep stuff from flying in you should be fine. What exactly tho are you needing help with? Are you needing direction on the best way to go about building it all into the trunk or how to just run the ports and such?

[Redford]

The car is a sedan (1995 camry le). Right under the rear deck the begining of the read deck, looking at it from the front towards the back, it is 12' tall and that part that is 12" tall is 4" long and 40" wide. Right after that part, there are the 6x9s and they are slightly over 16" from the bottom of the trunk (well... where the lining is, not planning to use wheel well). It starts getting slightly wider there too, but its diagnol so I think I'll stick with 40" for the width of the box. The hinges are out of the space that I want to use, so that won't be a problem.

Sorry about the old box in the pic... too much work to move it out just for a pic.


Well, I just need help with a few things:
Box size: what box size is the best? The bigger the better?
Port size: what kind of port is best? I think oval so it will fit just like the speaker hole.

I'd also like to know which of the following designs would render the most SPL (I guess you wouldn't know until you tried but what do you guess?)



I've never built a box before so that's why I don't really know what I need help with. What is important for me to know when building this? Basically you just build a box out of 6 panels, 1 or 2 have holes for subs and ports, whatever, and use a lot of screws every 3 or so inches. Do you need to add pieces of wood in the inside to brace the box?

[paikiah]

a single round port has smaller surface area than a rectangular port, so you might have to think about air turbulence (chuffing noises).

Also, you can use dual ports, but the length of the port will get longer. Perhaps a flexible tube would do the trick, since some of theport will have to remain inside the chamber?

[Redford]

Most of the port will be inside of the box. It's only a few inches from the top of the box to the speaker holes.

Do you know where I can buy oval ports or flexible tubing that would be wide enough for the ports?

[Alaxan]

Most of the port will be inside of the box. It's only a few inches from the top of the box to the speaker holes.

Do you know where I can buy oval ports or flexible tubing that would be wide enough for the ports?

What I would suggest (IF you are wanting to do a lot of mod to it) would be to make a new rear deck with a slotted port. SInce it is your first enclosure and oval port will be MUCH harder to calculate. What you can do is make it so the slotted port goes right up to the dash. BUT..... you could stay with a basic round portsince it will run up directly underneath the grill to cover it either way. I would also suggest facing the sub to the rear of the car in the design with two rounded ports directly under the speaker holes. Screws....every 3" should be fine, BUT you could do fine with 4-6" IF you utilize liquid nails in the process.

The biggest thing is BE CREATIVE! Take your own ideas of what will not only give a good sound, but also give a good appearance.

[Redford]

I think you're right that making slot ports would be easier both to build and calculate. I've been playing with WinISD a little bit but it can calculate port lengths for both circles and rectangles. Either way I don't think I'd be using an oval port as ports don't need to be very big so I wouldn't need ovals to use the speaker hole size efficiently.

I don't really wanna do custom work on the rear as I don't actually own the car, it's still technically my dad's and I don't want to do anything to lower the resale value (I plan to take this system with me, but will have to build a new box of course, to whatever my next car is whenever I can afford one).

Ok, now here's my last question, what frequency should I tune the box to? I know this is really a matter of preferance. I basically want the system to be mainly for SPL, but I don't want it to have horrible SQ and I'm not going to build 2 boxes. Perhaps I could have an adjustable/pluggable port system though.