If you don't need to know the air speed in the vent, click here to automatically calculate a port that is the proper size for your speaker enclosure. A general rule regarding port air speed is to try to keep it 10 percent or less of the speed of sound. Explanation of Terms W is the acoustic power output of the speaker in Watts. You can calculate this by multiplying the reference efficiency times the power handling of the speaker. Fb is the tuning frequency of the enclosure.
R is the radius of the port.
Mach is the speed of sound in air. To use this form, enter the values for W, Fb, and port radius.