Bass Reflex Calculator


In the realm of sound engineering and speaker design, understanding the dynamics of bass reflex systems is paramount. A bass reflex calculator serves as a valuable tool in this domain, aiding enthusiasts and professionals alike in optimizing speaker designs for optimal bass response.

How to Use

To utilize the bass reflex calculator, simply input the parameters relevant to your speaker design into the designated fields. These typically include the Vas (Equivalent Volume), Fs (Resonant Frequency), and Qts (Total Q factor) values of the speaker driver, as well as the desired tuning frequency and box volume.


The calculation of the ported box parameters, such as the port diameter and length, is based on the following formulas:

  1. Port Diameter (D):
  1. Port Length (L):


  • c is a constant (typically 1.463 for metric units or 5.787 for imperial units)
  • Vas is the Equivalent Volume of the speaker driver
  • ft​ is the tuning frequency
  • Vb is the volume of the box
  • S is a correction factor for the desired alignment (typically 0.707 for maximally flat alignment)

Example Solve

Let’s consider an example where:

  • Vas=20liters
  • fs​=35Hz
  • Qts=0.4
  • ft​=40Hz
  • Vb=50liters

By plugging these values into the formulas mentioned above, we can determine the port diameter (D) and port length (L).


Q: What is a bass reflex system?

A: A bass reflex system, also known as a ported enclosure, is a type of speaker enclosure that uses a port (or vent) to reinforce low-frequency output.

Q: What is Vas in speaker parameters?

A: Vas (Equivalent Volume) is the volume of air that has the same compliance as the speaker’s suspension system.

Q: Why is tuning frequency important in speaker design?

A: Tuning frequency determines the point at which the speaker and port resonance align, affecting the bass response of the speaker system.


In conclusion, a bass reflex calculator is an invaluable tool for designing speaker systems with optimized bass performance. By accurately calculating port dimensions based on speaker parameters and design goals, enthusiasts and professionals can achieve the desired sound quality in their audio setups.

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *