help with desing an spl sub box

[impulsed_sv6]

i have 2 type R subs 12" and would like to kno any infomation and making a spl box for them as i will enter sounds comps when i can

[acarmody]

Bit of light reading but there is some sound advice in here. Advice on building some SPL sub boxes

What boot dimensions can we work with here?

EDIT: Hmmm looking at the specs these things don't like large vented enclosures, Alpine recommends 1 - 2cu.ft vented. Maybe one of the installers has a different experience based opinion.

http://www.alpine.com.au/files/Owner...223d_1243d.pdf Quick reference for myself and anyone else.

[impulsed_sv6]

red through the post some very helpfull infomation on it i have been reserching bit more aswell and from the knowlage i have gatherd i have designe a rectangle ported box

h14xd13xw17 using 3/4 mdf giving me volume of 1.29 vb
less the sub displacment 0.07 giving me 1.22 vb
tuned to 33 hertz wich is what i belive the type R tuning frequcny to be
using one 2.2inch round port calls for a leng of 5.68 inches

what are your thoughts on building this

[acarmody]

First go 1" MDF, any panel flex will hurt your score. Second, go at least 2cu.ft, while bigger isn't always better, 1.2cu.ft is pretty small. Third go a bigger port, 2.2" is pretty darn small, maybe some 4" like I went, 6" if you can wrangle it.

[acarmody]

OK using 1" MDF, with outside dimensions used. 400mm height, 450mm wide, 500mm deep, single 4" port with length 300mm with 25mm flares on both ends, should give you 2cu.ft Vb, with a tuning frequency of 35hz.

[AmmoJammo]

you don't design an SPL box, you build it, test it, adjust it, till its right.

a single chamber box made from single layer 18mm MDF, and double layer for the baffle would be a good starting point, considering you may end up having to make another box anyway

somewhere around 100 litres total for both woofers.

you'll want to tune higher than 35Hz for SPL.

[AmmoJammo]

what numbers did your subs end up doing acarmody?

[impulsed_sv6]

ok went to the local car sterio installer who is very good at what he does
he told me to make
1.2vb
1.4vb
1.7vb
2.0vb

use n test all 4 boxs with different lenght ports with a 4 inch dia port
and try make the ports firing into the parcel sheld once i removed the infill panels and leave them blank directly firing them into the cabin

[vt josh]

6 inch port mate dont use anything smaller

[acarmody]

While I agree with Vt Josh here, I must point out it is quite hard to make two boxes with 6" ports in each that will get inside your boot. Like what happened with me.