# Subwoofer Vent Length Calculators

Calculate Length of Vent or Port

L=[2.35625×10^4×D^2×N]/[V×F^2]-K×D
L = Length of Vent or Port
D = Diameter of Vent
N = Number of Ports
V = Volume of Box
F = Tuning Frequency
K = End Correction Factor

Diameter of Vent:
Number of Ports:
Volume of Box:
Tuning Frequency:
End Correction Factor:

Result:

Vent Length:
Centimeter

Calculate Volume of Box

L=[2.35625×10^4×D^2×N]/[F^2×(L+K×D)]
V = Volume of Box
D = Diameter of Vent
N = Number of Ports
F = Tuning Frequency
L = Length of Vent or Port
K = End Correction Factor

Diameter of Vent:
Number of Ports or Vents:
Tuning Frequency:
Vent Length:
End Correction Factor:

Result:

Volume of Box:
Liter

Calculate Tuning Frequency

L=√[2.35625×10^4×D^2×N]/[V×(L+K×D)]
F = Tuning Frequency
D = Diameter of Vent
N = Number of Ports
V = Volume of Box
L = Length of Vent or Port
K = End Correction Factor

Diameter of Vent:
Number of Ports or Vents:
Volume of Box:
Vent Length:
End Correction Factor:

Result:

Tuning Frequency:
Hertz

Calculate End Correction Factor

K=1/D×([2.35625×10^4×D^2×N]/[V×F^2]-L)
K = End Correction Factor
D = Diameter of Vent
N = Number of Ports
L = Length of Vent or Port
F = Tuning Frequency
V = Volume of Box

Diameter of Vent:
Number of Ports or Vents:
Volume of Box:
Tuning Frequency:
Vent Length:

Result:

End Correction Factor:

Why do you need to determine the length to use for your subwoofer port?

There are several reasons, for example, the correct port length helps reduce subwoofer port noise. However, before we get into that, let's explain what a ported subwoofer box is.

A ported box or vented or bass reflex box is a sub box that uses a vent (a hole) cut into the cabinet connected to tubing or pipe attached to the port.

This hole or port is used to increase the efficiency of the system at low frequencies by channeling sound from the rear of the speaker diaphragm so that the box can be tuned properly.

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