SPL Box design

[mhuck123]

I have. 2 cube box for one 15 with a 8 inch port I'm doing a 147.9 smaller boxes have more imp mine is tuned to 51 hz

How does it sound on music?

[mhuck123]

Test and tune, then test and tune some more. Experiment with different designs and what not. looking at the specs on the website for the subs is a start. In a high power application, you may go a little smaller than recommended.

Website says 5-10 cubes so maybe the lower end and run 2 subs?

Also, should they have seperate boxes or loaded together?

[matt402]

Yeah the sub and port will be in the cab and the entire box will be in the trunk

It will be in a 1985 Olds Cutlass lowrider

with a big steel car like that, sound deadening is your friend .

are u sure u have enough room height wise to have the 18s standing up?

[Nightshade]

Spl boxes when walled should be large boxes, spl boxes that are not walled generally are smaller boxes. In your case since you aren't building a complete wall I'd say go with a smaller box. Probably around 4 cubes per sub, so 8 cubes in a common chamber. If it were me I'd try something like a 8 cube box with 2 9" flared ports whatever length you need to make them to tune them where you want them. That will give you 127sqin of port and 15.9sqin of port per cuft. It's a good starting point and you can always add more port area to try to get louder. First off you need to find the resonant frequency of your vehicle.

This can be done by using a 10" or 12" woofer in a sealed 1 cuft box and playing tones from 20-80hz and recording which frequency is the highest spl. Whichever is the highest is your resonant frequency. Since you are planning on having the subs in the cabin part of the car you need to place the enclosure there and then test instead of having it in the trunk. If your going to do sound deadener do it first before you try to find your frequency.

Once you find your frequency then you can build the box and decide what length to make the ports. If you want to do a slot port instead of flared round ports(I don't reccomend a slot port unless it's a wall) you should probably go with around 180 or so sqin of port for a 8 cube box.

[matt402]

common chamber box with a lot of port.

[mhuck123]

with a big steel car like that, sound deadening is your friend .

are u sure u have enough room height wise to have the 18s standing up?

Wont be standing up, will be fireing forward. Basically I am removing the rear seatback and the woofer will be there firing forward.

I have 2 layer of Dynamat Extreme already installed on the roof and floor and 1 layer in the doors behind the brace (on the sheetmetal itself. I have 10 more sheets and will be doing the entire car and maybe another layer of the dynamat heatshield on the floor too. The roof is solid feels like hitting a brick wall.

[mhuck123]

Spl boxes when walled should be large boxes, spl boxes that are not walled generally are smaller boxes. In your case since you aren't building a complete wall I'd say go with a smaller box. Probably around 4 cubes per sub, so 8 cubes in a common chamber. If it were me I'd try something like a 8 cube box with 2 9" flared ports whatever length you need to make them to tune them where you want them. That will give you 127sqin of port and 15.9sqin of port per cuft. It's a good starting point and you can always add more port area to try to get louder. First off you need to find the resonant frequency of your vehicle.

This can be done by using a 10" or 12" woofer in a sealed 1 cuft box and playing tones from 20-80hz and recording which frequency is the highest spl. Whichever is the highest is your resonant frequency. Since you are planning on having the subs in the cabin part of the car you need to place the enclosure there and then test instead of having it in the trunk. If your going to do sound deadener do it first before you try to find your frequency.

Once you find your frequency then you can build the box and decide what length to make the ports. If you want to do a slot port instead of flared round ports(I don't reccomend a slot port unless it's a wall) you should probably go with around 180 or so sqin of port for a 8 cube box.

NICE, very specific! Now I just have to find someone with an RTA I can use in Souther California.

[matt402]

thats what i meant ^, u need ~20" height in ur trunk though...

[rmzsuzuki89]

How does it sound on music?

If it's going to be a true spl box, odds are that it wont sound great on music for daily.

[mhuck123]

If it's going to be a true spl box, odds are that it wont sound great on music for daily.

Forgive me if I'm wrong but if I play it daily around 135-140 would it sound OK?

Hell I'll just play songs in the frequency range of the box if I have too! I have another car for SQ