Thread: Well, I bought some speakers..

hang on a sec and I'll send you a link

hey I can get you one of those boxes unloaded.... that would be the ticket

Just make your own box. It's much more cost efficient. $20 sheet of MDF,$5 for titebond wood glue, $5 screws. $30 box thats accurately tuned.

It actually very easy. There are a few formulas to determine the length of the port. I like this one.

Lv=[(14630000xR^2)/(Fb^2xVb)]-1.463xR
Lv= port length
Fb=Tune frequency
Vb= cubic ft x 1728.

Slot
R= SQrt (A / 3.14)
A= L x W of port area
Round
R= inside radius of vent tube

Now the 1.79 with a 4"x10" round port is around 40hz give or take a lil, only 12.5" of port area. Not enough airspace or port area and also tuned too high if you ask me. I'd shoot for 2.0cu ft @ 35hz. So lets get started.
1.Determine how much port area you need.
Most 12"s will be fine with 20 sq inches of port area (I did 1.75 x 12.5 = 21.875 as this will be for a b13)
2. Find R (Square root of (port area / 3.14)
sq rt (21.875 / 3.14) = 2.6394
R = 2.6394
3. Determine Fb(tune frequency) in this case 35hz.
Fb=35
4. Determine Vb(internal airspace) in cubic inches.
2.0 cu ft x 1728 = 3456 cubic inches
Vb = 3456
5. Solve formula. [(14630000 x 2.6394^2 / (35^2 x 3456)] - 1.463 x 2.6394
[(14630000 x 6.966) / (1225 x 3456)] - 1.463 x 2.6394
[101918905.4268 / 4233600] - 1.463 x 2.6394
24.073 - 3.861 = 20.212
Lv= 20.212 lets say 20 1/4".


Now onto figure the box...I'll do this for a b13.

1. Find desired internal air (2.0cu ft), Port area L x W (21.875 sq inches)
2.*** Find port displacment (L x W + wood thickness x H / 1728). Assuming your using 3/4"mdf and one port wall being the outer side of the box add .75 to the overall port width(1.75 + .75 = 2.5). If your port has 2 walls inside the box make sure to account for it.
20.25 x 2.5 x 12.5 / 1728
632.8125 / 1728 = 0.366
.366 is your port displacment
3. Add displacments to internal air. In this case 2.0(air) + .366(port) + .094( P3 sub) = 2.46
4. Find max dimensions of box L x W x H you can use in your car. I went with 35 x 14 x 14 Pick 2 and multiply not to forget to subtract wood thickness. 33.5L x 12.5H = 418.75
5. Find length of remaining side. S=(2.46 x 1728 / 418.75)
s= 10.1 <---this is internal, add wood thickness when making the box.

So a box that is 35"long 14"high and 11 5/8"deep (10.1 + .75 + .75) with a slot port 1 3/4" wide and 20 1/4" long will be 2.0@35hz.

***To determine round port displacement use this formula.
(3.14 x radius^2) x length / 1728

That would be very good. Let me know!
http://www.rockfordfosgate.com/products/product_details.asp?cat_id=17&series_id=56&family_id=58&item_id=108298&locale=en_US&p_status=

That without the P2 would be perfect.

LMFAO,,,,, that would work if you want a standard square box, it's up to you Brett ,, I'll get you the price this weekend..

haha, that's fine, and it's already ported and such. The cu.ft is just about right too, little large, but not too bad. I'm in a hotel for the next few days, so if you want, call my cell phone if you find anything out. Thanks man!

got 'em put in saturday night. they're really nice. good clean sound. the woofers hit hard, and the tweeters balance out my bass. It's pretty nice. my friend was driving next to me in his mx-6 with an open downpipe and was able to hear my stereo over his exhaust.. i think i lost some hearing. it's perfect though, i now get a full range of sound without having to turn it up too loud.

LOL,,, sweet ,, post up some pic's let us see

not saying they can't .. but I've been to spring break nationals a few time and I've never seen anyone with that stuff come even close to 150 Db and if they are hitting that hard ,, why are'nt they going where the big boys play??.. DAYTONA BABY !!! if your bad you show up and play if your not you show up and keep it quite!! ..

and BTW your ears CAN"T HEAR 28 hz,, dogs can

so you think..

i'm weird enough to hear down to 17hz. it's actually really weird, because it's just a feint sound at that point, but i can still hear it.