Port area for a single 12

[UhOh Spaghetioz]

Add an inch to the port for end correction.

Correct.

Torres adds in end correction but it seems like the tuning is always lower than calculated. It auto calculates one flanged and one free which should be correct when using an aeroport.

For example, if you have a 6 inch tube in between 2 flares, your port length would be 12" (if each flare is 3"). I would type 13" into torres as your length and the tuning will probably be closer to that than if you type in the real 12" physical. Box size, box position, and other things affect how close the tuning will be as well.

So since torres says 11.5" i just make the tube 12.5" then put the flares on?

[SCS_Audio]

No. Your physical length should end up being about 1 inch shorter than the theoretical length in torres. Also, the flares count as port length just like the tube in the middle. If it says you need 13" port length to get to your desired tuning, chances are you might only need about 12" physical length. This would mean a 6" tube with a front and back flare.

If you have the ability to easily remove the port and cut it, you could start with it exactly as torres says and cut some off the tube if it ends up being too low. I have never missed a tuning on the high side using torres or WinISD. They usually are low by a couple Hz