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Ported woofer box

How to build and design a ported woofer box





Ported or "Tuned Ported" box

Ported enclosures use a tuned port or vent to increase output at lower frequencies. Air inside the port acts like a piston or motor that moves in phase with the woofer, reinforcing the frequencies response.


Ported enclosures are distinguished by a vent or duct in the structure. This vent allows the rear sound wave of the woofer to interact with the front sound wave. The coupling of a vent to the air inside the enclosure reinforces the low-frequency response of the subwoofer system and can greatly increase the efficiency. By changing either the length or surface area of the port, the resistance to motion of the column of air within the port changes its resonant characteristics, thus causing the tuning frequency of the enclosure to change.



Pros :

  • Small box designed 

  • Higher power handling

  • Excellent dampening in transient responses

  • Easily to design and build

  • Can be forgiving of design and construction errors


  • Limited efficiency

  • Output


Box Design




Speaker enclosure types


Speaker boxes design


Sealed box


Ported woofer box


Infinite baffle


Sealed Inverted




Speaker polarity and impedance


Speaker wiring:Parallel, Series, Series-Parallel





Woofer box calculators index


Calculating speaker enclosure volume


Rectangle sealed enclosure volume calculator


Circle port to slotted port calculator


Triangle Box volume calculator


Parallel- Parallel Load Calculator


Port length calculator


Series - Parallel load calculator




Bass cancellation






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