Cab builders

[knuckle_head]

I know what it will take to tune a specific cab a specific way using tube ports - is there a way to re-shape the ports to a rectangle fairly simply or do I need to re-model the design and have the rectangular port calculated?

tia

[rpsands]

IIRC, the area and depth of the port is what matters. So a 3" circular port (1.5^1.5*pi area -- 7.07 square inches would perform the same as a square port 2.66" on a side.

* Shelf ports are different because they get to use walls of the cabinet as length of the port -- so they calculate differently.

[knuckle_head]

Originally Posted by rpsands

* Shelf ports are different because they get to use walls of the cabinet as length of the port -- so they calculate differently.

Well this concerns me . . .

I'm changing the footprint on a 15/6 and intended to merely move the ports.

[rpsands]

Originally Posted by knuckle_head

Well this concerns me . . .

I'm changing the footprint on a 15/6 and intended to merely move the ports.

It can be pretty goofy because you have to iterate, and deduct the volume of air behind the port from the cabinet volume, to get precise results. This is per Greenboy, hope I am explaining it right.

My experience has been that the car stereo calculator seems to get close enough for gubmint work, but if it were me and I wasn't drastically changing the dimensions, I would just copy Greenboy's shelf depth and port area and hope for the best.

[knuckle_head]

Originally Posted by rpsands

. . . I would just copy Greenboy's shelf depth and port area and hope for the best.

my plan - succeed or fail

[rpsands]

Originally Posted by knuckle_head

my plan - succeed or fail

If you want to check yourself you can compare the volume of the area behind the port in your design, vs. greenboy's. If it's really close, you're probably in the clear.