Too Much Port Area??? (8" Port, 3 Cubic FT)

[Mr.SoloDolo 10+ year member]

I have a sealed 3 cubic ft. Enclosure for (2) 12's

Thinking about inverting the subs and throwing in 8" Sonotube internally.

Shop Sakrete 48" Concrete Forming Tube at Lowes.com

Will this be to much port area for the enclosure.

Length with be 33" Tuned to 34hz

Go for it or not?

Click to read more...

 

[dB-SPL 10+ year member]

Not sure how you're doing your math, but something's not adding up correctly. If you just jam a 8" x 33" tube in a 3 cube box, you're lookin' at under 2 cubes and over 40hz. And the displacement is WAY more than .029 on a port that size. That's about a cube alone.. So to answer your question. That's around 25" of port per cube. That's a LOT. In the 'too much' range..

 

[RAM_Designs 5,000+ posts]

Bad idea, like stated above. Your net volume is going to be way too low, and the tuning will be way too high.

 

[Mr.SoloDolo 10+ year member]

I'm trying to stay @ 3cubes and run some sort of aeroports but it seems like nothing will fit.

I used psp calculator btw

 

[dB-SPL 10+ year member]

If you want to keep that same box and stay around 3 cubes, your only option is to run external ports..

 

[Mr.SoloDolo 10+ year member]

I was hoping to do something like this but down the side of the enclosure

I guess i'll do external...

 

[dB-SPL 10+ year member]

I was hoping to do something like this but down the side of the enclosure

I guess i'll do external...

Wow.. That port is choking. Far to close to box wall.

 

[sacsking916 5,000+ posts]

External aeros are your new best friend

 

[Mr.SoloDolo 10+ year member]

Wow.. That port is choking. Far to close to box wall.

True but if I inserted it through the side I would give it more room from the port wall.

Seeing that having the port internal will bring me down to 2cubes i'm going to go another route...

Thanks for your help

 

[dB-SPL 10+ year member]

Just do one 6" port. Mount it to a 3/4" MDF circle from inside the box with a total length of about 17.5". That should leave you with 3 cubes @ 34hz with just over 28" of port area. It's not a huge amount of port area but it's over the minimum 'rule of thumb' for aero's.. Aero's don't need as much area as slots, squares, etc.

 

[Mr.SoloDolo 10+ year member]

Just do one 6" port. Mount it to a 3/4" MDF circle from inside the box with a total length of about 17.5". That should leave you with 3 cubes @ 34hz with just over 28" of port area. It's not a huge amount of port area but it's over the minimum 'rule of thumb' for aero's.. Aero's don't need as much area as slots, squares, etc.

Last resort i'll go this route.. thanks for crunching those #'s for me

Might just build a box 4cubic ft. with the one 8" aero and subs inverted to give me about 3cubes net.

 

[bgowdy 5,000+ posts]

how are you guys calc these numbers. i need help