Calculating Port Air Speed

This calculator is intended to help you determine the speed of the air in the port.

This will help you decide if a particular port is too small for your application, which will cause noise at high volume levels.

This calculator is not intended for use on bandpass designs.

A general rule regarding port air speed is to try to keep it 10 % or less of the speed of sound <= 342 meters

Explanation of Terms

  Pak is the acoustic power output of the speaker in Watts.
( You can calculate the Acoustic Power ( Pacoustical ) using this link Efficiency Calculator )
Fb is the tuning frequency of the enclosure.
R is the radius of the port.
Mach is the speed of sound in air (342 m/sec).


Pak acoustic power :

Fb tuning frequency of the enclosure :


R radius of the port. :


% of Mach

Click here to calculate the Driver Reference Efficiency

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