View Full Version : ****Help me design a box for my Shivas****

05-20-2004, 06:40 AM
I have about 44" in width and 15" in height to work with in my trunk and it is about 40" deep. My problem is that I bought two Adire Shivas and they are totally different from my old Pioneer Premier SPL woofers, so I am designing a new box for them. I have read Adire's home audio box designs that the box should be about 3cu. ft. and vented to about 20 or 22hz. They also have the woofer firing downward so it has an increased Xmax. My only problem is that their stock designs will not fit in my car and so I need to custom build something.

Would any of the experienced members be able to help me out with a design?
I really want these to sound good and my knowledge on the type of enclosure I'm going to build is limited.

Here are the parameters for the Shiva:
Re 2.9 ohms
Le 2.12 mH
Qms 6.5
Mms 125 grams
Qes 0.40
Cms 0.47 mm/N
Qts 0.38
Rms 2.54 N*s/m
Fs 21 Hz
Sd 481 cm^2
Vas 151 liters
BL 11.3
Xmax 16.6 mm one way
EBP 51
SPL 87.3 dB @ 1W/1m
No 0.37%

***If I left anything out you might need to help let me know.***

05-20-2004, 03:46 PM
Make sure you can fit this box in the car. I highly doubt that you could, so you may want to remeasure. You only need half of the size for the subs. I would say do about a 7.5 cube before displacement and use about 60 sq inches of port area.

Design the length width and height and do a slot port. (ex. 13.5" h x4.5" w for the size of the port)
Plug it into the ported box formula on www.jlaudio.com and find the port length. It will probably be pretty long so I would start with about 30 and see what it does from there.

When you calculate volume, remove 1.5" for wood. That is how I came up w/ the 13.5 for height of the port.

As far as downfiring, that is for home audio. I also wouldn't tune to 22 hz. I would tune it to around 28 hz. My friend's tempest is tuned to 24 hz and it is perfect for the 15, but this is a 12, so it should be a little higher. I would also put the subs and port on the same plane.

05-20-2004, 06:19 PM
I know I can probably fit it in. My trunk is something like 15cu ft and the trunk lid is pretty wide. Although that 15cu ft includes every nook and cranny. Plus I'm trying to save room for the amp rack I have to build. so I'm shaving some off of the height for that.

Ok, so no downward firing for this project... Which would be better then, having my subs and ports facing my backseat or having them facing the trunk? Will I be fine at 28Hz SSF wise because I only have this darn JBL 1200.1 and a set of 20hz Fmods? I want to make sure I don't damage my subs.