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How to Calculate Port Length in a Corner

Subwoofers are used to add depth and bass to the sound coming from stereo speakers. You can increase the sound quality of your subwoofers by connecting them to port tubes. These port tubes transmit sound from within the subwoofer box. Calculating the port length when placing your subwoofers in a corner helps with the acoustics as the length can vary from location to location. Once you have calculated the port length, you can determine the modifications needed to create the clearest sound to meet your requirements.

Things You'll Need

Measuring tape

Instructions

- 1
  Measure the height, length and width of your subwoofer with your measuring tape. Multiply the three values together to get the volume in cubic inches.
- 2
  Measure the diameter of the port tube in inches with your measuring tape. Calculate the measurement from the distance of one edge of the circle to the exact opposite edge.
- 3
  Decide between the 45 hertz (Hz) or 25 hertz (Hz) to use. The louder the hertz you select, the lower the sound quality will be. This is not a measurement, but you will need to decide what level of hertz you will use to enter into your calculation for Step 4.
- 4
  Calculate the port length for your subwoofer in the corner by using the following calculation:
  
  ((14630000*(diameter/2)*(diameter/2))/((frequency*frequency*volume*1728)-(1463*(diameter/2))))
  
  Replace "volume" with the volume of your subwoofer, replace "diameter" with the diameter of your port tube and replace "frequency" with your hertz selections. Your calculation should come out in inches.

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