Unknown box tune, how do I figure out what its tuned to.

[WOT]

Im trying to help a friend build a setup for 2 15's. And we found a box locally that will fit his truck, but the guy doesnt know what its tuned to. The box looks great and solid, he just says he forgot the tune hes had it so long.

Its a basic slot port box, port back subs up. Using 1/2" MDF

Box- 24"deep / 37.5" wide / 18.25" high

The port is 6.25" wide X 17.25" high and 16.75" deep

Im havin trouble trying to figure out exactly what the box is tuned to. Hoping to pick this box up before it gets sold.

Thanks for any help

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[Fiercetimbo17 10+ year member]

If my math is correct about 32 hz.

 

[qtipextra 5,000+ posts]

BassBoxPro is saying it's 40hz.

 

[WOT]

hmmmmmmm, 32 or 40. I see you punched in all the right numbers though

 

[chaunb3400 10+ year member]

if its a prefab probably around 40hz

 

[thehardknoxlife 10+ year member]

BassBoxPro is saying it's 40hz.

Did you enter the port displacement correct? If the box uses one of the outside walls as part of the port then the port thickness should be .25 because BBP calculates the port as having 2 walls, at least the version I have does.

 

[qtipextra 5,000+ posts]

Did you enter the port displacement correct? If the box uses one of the outside walls as part of the port then the port thickness should be .25 because BBP calculates the port as having 2 walls, at least the version I have does.

Im not so sure that is correct. While BBP figures 2 port walls, it is figuring inside dimensions, so walls dont matter. (At least to my understanding, I could be wrong)

However the difference is so small that it isn't going to make any difference either way.

 

[cshaw 10+ year member]

play a slow sweep or play tones and find out where the least excursion is.

 

[qtipextra 5,000+ posts]

play a slow sweep or play tones and find out where the least excursion is.

That is nearly impossible to tell by eye. Math is better the eye-balling.

 

[cshaw 10+ year member]

eh, it gets you close, helps to have a laser pointer too.

 

[bass-aholic 10+ year member]

As said if its a prefab its probably 40hz to high 40's. And DONT BUY IT!

 

[WOT]

if its a prefab probably around 40hz

A prefab box that big? No. Its a custom box

And we dont have any subs to test excursion etc, its just sitting in the guys garage. Was hoping math would prevail

 

[qtipextra 5,000+ posts]

A prefab box that big? No. Its a custom box
And we dont have any subs to test excursion etc, its just sitting in the guys garage. Was hoping math would prevail

It has. It's 40hz give or take a few tenths of a hertz.

 

[WOT]

Alrighty, thats prety much perfect for the subs hes buying. HDC3's

And it works out to 8+ cubes to eh.

Freaking perfect!

 

[Fiercetimbo17 10+ year member]

Looks like my math was a little off, however winisd is saying 39.3 if you take the displacement of the subs and a semi guess on the port.