Help with sub box design.

["350Vortec"]

Hey guys need some help here.

Heres my setup now.

-Dual 12" Rockford Fosgate HX2'S 1,000 Watts
-Sealed Single chamber box
-Rockford Fosgate 800 watt amp.

They are really loud on higher notes but lows...its sounds likes shit. Like its gasping for air.

I want to try a ported box but never even knew where to begin. If you guys could please just design me one i could even throw you $5 through paypal or something.

I need it in simple measurements. Like all the external measurments. Im not good with calculating shit at all.

Heres my subs and there rating.
http://www.crutchfield.com/p_575RFD2212/Rockford-Fosgate-Punch-HX2-RFD2212.html?tp=111

Thanks in advance guys.

Remember i have a 2 door with a spare tire mounted in back so..I dont have tons of room.

Not sure if it helps but here is the owners manual.

http://akamaipix.crutchfield.com/Manuals/575/575RFP4208.PDF

 

[blueflamed03]

I'll post more on this in a few when I have a few seconds...

 

["350Vortec"]

Thanks man. Appreciate it.

 

[blueflamed03]

pretty broad range, 1.75-4/0 per driver. Usually bigger is better, but not 'too' large.

Ok, calculating enclosure.

Measure the distance between wheel wells, and from back seat to teh tailgate how far your willing to sacrafice. Then, measure height, so it fits under the seat, and possibly window line. So (all examples now)

say you have 37" across between wheels, and say you can do 20" depth, and 22" tall..
You plan to build the box out of 3/4" MDF. (I would)
Inside dims, you have around 7.80 cu ft, so 3.9 per driver. So you can see, you really can make the box much smaller.
Play with the box side, and use this good calculator. Plan on a divider in the center, to have two chambers. (just me, some like a common chamber.
http://www.rockfordfosgate.com/rftech/box_wizard.asp

1) rectangular
2) standard
3) 3/4" MDF
4) outside dims



Now once you get around say 2.50 per driver, go to this site, and calculate port length.
http://www.carstereo.com/help/Articles.cfm?id=31

down on the bottom, you see Calculate your port length.

enter in round port, qty 1 (doing one per side), enter enclosure volume (IE 2.50) and tuning I did 35hz, and a 4" PVC pipe for port.
Hit calculate and it shows a 4" round port, around 8.13" long. That's how big you make your port per chamber. Usually you minus port displacement, but your really talking apples here, so you know if your box is like 2.75 per side, it will be dang close to 2.50 after your 4" port, 8" long.
make sure all joints are glued, nailed then siliconed inside.

This is a quick rough to play, not exact science by any means, but at least this gives you the tools, and websites to play with boxes.

 

["350Vortec"]

Damn Blue! That helped me out a TON. haha. I really appreciate it man. Kudos to you. I am now confident i can build a decent box this weekend. Your the man!

 

[lilJohn]

Here is a great calculator if you wanna do a slot ported box. It will tell you everything what it is tuned to and better yet a cut sheet so you know exactly how to build it. I have done three boxes for my boat using this calculator and they have all been very successful.


http://www.reaudio.com/speaker_box/LPort_Box_Calc.html

 

[Rollin Thunder]

build box. cut holes in front, thanks wheres my 5 bucks?

 

["350Vortec"]

build box. cut holes in front, thanks wheres my 5 bucks?

Good job. You have basic caveman skills. Ill give you an A+ for that, not $5.

---------- Post added at 07:03 AM ---------- Previous post was at 06:34 AM ----------

I decided to use my current box and fabricate it a bit. Im going to add a divider. And a port on each side, But where is the best place to fire the ports from. Top? Rear? My subs will be facing me if you open my barn doors. So....

Another question, Why is is that if you go smaller diameter for a port it needs less length to tune at 35 hertz? But a 4 inch one needs to be way longer to tune at 35 hertz?

 

[blueflamed03]

don't go less than 4" or you may get port noise. Face woofers and port toward the rear tailgate.