ported box help...check my calculations..

[Devin_9_2004 10+ year member]

Hey guys,

I'm going to build a ported box and would like someone to double check my calculations.

The outer dimensions will be 17.5 x 17.5 x 31.5.

The gross internal volume is 4.44 cubic feet.

The port will be 16 x 3 x 32.

The sub displacement is .18 cubic feet.

The port displacement would be 1.11 cubic feet

A final net volume of 3.15 cubic feet tuned to 33 hz!!!

Hopefully I'm right!!

Thanks,

Devin

Click to read more...

 

[Devin_9_2004 10+ year member]

the port will have a 90 degree bend. It was going to go the full length on the the right side where the length of the wall would be 16.75 and make a turn to the left another 15.25 inches...would would start being measured from the left side of the port wall.

 

[Devin_9_2004 10+ year member]

http://client.webshots.com/photo/211948761/211972395liNyBI

I made a diagram for you lazy folk.... Anyone?

 

[tRiGgEr 5,000+ posts]

Hey guys,
I'm going to build a ported box and would like someone to double check my calculations.

The outer dimensions will be 17.5 x 17.5 x 31.5.

The gross internal volume is 4.44 cubic feet.

The port will be 16 x 3 x 32.

The sub displacement is .18 cubic feet.

The port displacement would be 1.11 cubic feet

A final net volume of 3.15 cubic feet tuned to 33 hz!!!

Hopefully I'm right!!

Thanks,

Devin

I didn't check but did you calculate the end correction?

 

[Devin_9_2004 10+ year member]

ok...The port displacement is not 1.06. (3.75 x 16 x 32) / 1728 = 1.11.. As far as end correction goes it was not calculated. I don't even know what that is. Hopefully someone could shed some light.

Thanks,

Devin

 

[tRiGgEr 5,000+ posts]

ok...The port displacement is not 1.06. (3.75 x 16 x 32) / 1728 = 1.11.. As far as end correction goes it was not calculated. I don't even know what that is. Hopefully someone could shed some light.
Thanks,

Devin

Just deduct 1.5" from your port length. Because you are using a wall of the box as a wall of the port. The wall keeps going when your port stops. So a port correction of half your port width is required.

 

[iceteebone 5,000+ posts]

somebody make sure it's correct //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Devin_9_2004 10+ year member]

ok so the other guy was right with the 1.06 for displacement. Is there a place where i can read a tutorial on end correction? I'm not following what your saying triger...sorry im a little slow. I just turned the port into 2 seperate boxes. One going straight to the back of the box and one going from the left edge of the port to the end of the port. Why is this not correct?

 

[Devin_9_2004 10+ year member]

i just did the calculations for end correction and it hardly changed...it went from 3.15 ft^3 to 3.2 ft^3 and the tuning changed from 33 hz to 32.8 hz....