Can someone design me a box for 2 alpine type - r SWR-1222D

36" wide and 24" deep? what about the height? and are you sure that will fit? Also what amp are you using?

 

you'll want to be right around 5 cuft +-.2 cuft with a tuning of 38hz

 

I think we wanna shoot for around 4 cu ft for two woofers. So lets try a box that is 36-inches wide, 14-inches tall and 18-inches deep. That should give us an internal volume of just over 4 cu ft. (assuming your using 3/4-inch MDF)

Now for the port. Lets not put it between the two woofers. Put it on the side. This will make it 12.5-inches tall. Make it 3.5-inches wide and 14-inches long.

Now if this box is in an SUV, the port needs to be placed on the driver side and facing the rear of the SUV

Now check out post #3
http://www.caraudiotalk.com/audio-forum/showthread.php?t=6856
Building the box this way simplifies construction.

 

is that for all suv's, and why?

 

When we listen to the bass, it doesnt matter where the port is. It all sounds the same to us. But not to the microphone. The port is tuned to a specific frequency and that frequency has a specific length.

A frequency of 30 Hz is around 450-inches long. This wave cannot fully develope in an SUV. The half octave and the quarter octave points in this wave will cause the mic the see the most intensity. So at 225- inches and 112.5 -inches will have the max reading.

The mic reads the intensity of the wave at a perticular point in time. NOT how loud it is. So the futher we have the port from the mic the better (but not always). The speaker can be closer because it generates more than one frequency.

Now this is not all there is to this. We still try to match the Box peak frequency (not the tuning frequency) to the vehicle length to maximize the intensity

There is a little more to this

 

why not 5 cuft ranger?

 

i just built a test box for one of my 12 inch type Rs and it was about 2.5 cu ft and tuned to about 38-40 hz, somewhere in that area. that thing slams way harder than any of my previous double sealed set ups (had kicker comps and kicker cvrs). you should try a box around that size and you can give the alpines more than 560w rms. i know they are 500 rms, but these things take a good pounding, give them like 750 a piece

 

2.5cuft per sub or both? if one then thats pretty much exactly what i was going for.

 

it was just a test box cuz i never built one before lol. but yeah i did it for one cuz i was reading that you guys recommended it and it worked out really nice, thanks

 

At some point we will start to loose control of the woofer. While 5 cu ft would probably work, I think we are starting to push.

Now for one sub that recommendation is on the money, also if we were building a divided dual sub box, then I would recommend 5 cu ft.

 

My box is 5.25ft^3 and my subs do fine. But then again i am only runnin 200RMS each. It gets crazy loud for that wattage though.

 

because you increased the drivers efficiency.

Now ranger i kind of understand how having just one big box for two subs as opposed to a divided enclosure for two subs but with the exact same volume would sound different. Is this affected by the port? I'm assuming one central port would play the biggest roll. Also in a large box for two subs what would happen if you used two seperate ports and put them at opposite ends of the box considering port surface area is the same and they're on the same plain? Sorry for rambling on and on btw.

 

If I confuse everyone (including myself) Anz will save us. When we have two subs in one enclosure, the subs act as one. Think of it as one sub in one enclosure.

OK, multiple ports tend to work well if they are seperated slightly. But they need to be on the same side (did I word that right?). We cannot have a port on the rear of a box and one on the front. Also, a port cannot be on the side opposite the speaker. While it can be made to work, typically it won't.

 

What if i have four ports in my 5.35ft^3 and two are in the middle on the front, and 1 on each of the sides, and arent separated at all? Have i made my box not perform well when i did this?

 

usually ports on different sides each load different changing the tuning of each slightly

 

Thats what i thought, so is this making my box poorly designed?