Blu84Rex

01-31-2007, 09:29 PM

I am trying to figure out the math and I am getting stuck on the port length & tunning on a box for 2 12" type r's.

Outside measurements are 40" wide, 15" High, 15" deep.

Which brings the gross volume to 4.06ft^3 and after driver displacement 3.91ft^3.

The local stereo guy says that the port measurements should be

13.5" high

2.75" wide

15" deep

That would tune to 38hz

I would like to tune somewhere closer to 33hz. What would the length of the port have to be for that?

I also have a couple of math questions. How do I find out the displacement of the port and how do I measure the port? do I start from the outter face of the box and stop 2.75" from the back and start from the side and go over the remaining distance.

Outside measurements are 40" wide, 15" High, 15" deep.

Which brings the gross volume to 4.06ft^3 and after driver displacement 3.91ft^3.

The local stereo guy says that the port measurements should be

13.5" high

2.75" wide

15" deep

That would tune to 38hz

I would like to tune somewhere closer to 33hz. What would the length of the port have to be for that?

I also have a couple of math questions. How do I find out the displacement of the port and how do I measure the port? do I start from the outter face of the box and stop 2.75" from the back and start from the side and go over the remaining distance.