First box built, thumping hard( pics included) and bottoming out..plz help

[melb-bass]

I have finally finished my first box designed from scratch... Its all built and thumping hard, it sounds great hitting lows and shaking the car. Currently running off a kicker zx.750.

This is just a beginners box so i can learn the skills of box making and calculating, i am hoping to upgrade to some good quality subs in the future.

Still have to add another battery and change my 2gauge big 3 to a 0gauge big 3, and stronger alt...

Dimensions(external)

H: 15.5in

W: 31.5in

D: 23.5in

Port

H: 15in

W: 4in

L: 12in

From memory it should be 5cu ft.

Here are some pics.

I am thinking about doubling the port length to get it down to 28hz, because i think now its at 32hz.

I dont understand how to calculate port size and length, i just need someone to explain that to me. All the volume of ports and all that... Its the only part i guessed with this box. If someone can help me understand how to calculate port it would be great.

Neways i hope you like the box and can provide some assistance.

Also thanks to everyone on this forums, helped me heaps.

Edited October 6, 2011 by melb-bass

[That1Kid]

Download Torres Box Calculator. It's stickied here.

[^_^ Gem132]

Download Torres Box Calculator. It's stickied here.

This, you will use it multiple times for further upgrades etc, you cnt go wrong with it

[melb-bass]

thats what i used to make this box, also used bass box pro.

I just didnt understand all the port volume and area, and how much i need for a box haha.

[727Designs]

Well, first your port is only 14 if your box is 15.5 tall. If so that will throw you at 4.73 net after port, but before sub displacement. Your tuned at 40hz with 11.8in^2 per cube. Box is probably on the big side for those subs.

[melb-bass]

Audiobahn provided some specs for the subs, they need total 3.5cu. ft. each. and 3.2 after port... so with trunk space i have to cut back, which i did.

Unless i have thought of the concept wrong, I assumed each sub needed its air, so i kinda doubled everything i worked out for a single sub. Should i just make the box 3.5cu ft. total for both subs or does each woofer need its own air?

Sorry for all these questions... Noob wanting to learn.

Cheers guys

[melb-bass]

Can anyone help me...

When you have 2 subs, doesnt it mean the box is doubled, to give each sub the air, or does it just share the box..

So for example, 1 sub requires 2cu ft box, does that mean 2 subs need 4cu ft??? thats the way i went with this....is that correct

thanks

[dtleonard26]

Yes 2 subs are double air space compared to one

[727Designs]

Audiobahn provided some specs for the subs, they need total 3.5cu. ft. each. and 3.2 after port... so with trunk space i have to cut back, which i did.

Unless i have thought of the concept wrong, I assumed each sub needed its air, so i kinda doubled everything i worked out for a single sub. Should i just make the box 3.5cu ft. total for both subs or does each woofer need its own air?

Sorry for all these questions... Noob wanting to learn.

Cheers guys

3.2 per seems big for a low line 12" to me, then again I suppose I could be wrong as I haven't dealt with much Audiobahn stuff.

[melb-bass]

I was surprised myself with the amount of air it needs....But these do hit hard, harder than i expected.

Do you think if i make my port longer so its lower tuned, it would be good?

Also as i said, this is all just practice till i learn enough to go BIG.