Woofer Port Calculations


Length of Port Volume of Box Tuning Frequency End Correction Factor
Information about the End Correction Factor
More Information About Reflex Tubes & Ports ( ext. Link )



Calculate Length of Port (L)




Dv = Diameter of Vent Np = Number of Port(s) Vb = Volume of Box
fb = Tuning Frequency k = End Correction Factor Lv = Length of Vent


Dv :
Np :
Vb :
fb :
k : Normally k = 0,732


Lv = Centimeter






Calculate Volume of Box (V)


Dv = Diameter of Vent Np = Number of Port(s)s fb = Tuning Frequency
Lv = Length of Vent k = End Correction Factor Vb = Volume of Box
Dv :
Np :
fb :
Lv :
k : Normally k = 0,732
Vb = Liter






Calculate Tuning Frequency (F)


Dv = Diameter of Port Np = Number of Port(s) Vb = Volume of Box
Lv = Length of Vent> k = End Correction Factor fb = Tuning Frequency
Dv :
Np :
Vb :
Lv :
k : Normally k = 0,732
fb = Hertz






Calculate End Correction Factor (k)


Dv = Diameter of Port Np = Number of Port(s) Vb = Volume of Box
fb = Tuning Frequency Lv = Length of Vent k = End Correction Factor
Dv :
Np :
Vb :
fb :
Lv :
k factor =






Information about the End Correction Factor (k)


In acoustics, end correction is a short distance applied or added to the actual length of a resonance pipe, in order to calculate the precise resonant frequency of the pipe. ... A theoretical basis for computation of the end correction is the radiation acoustic impedance of a circular piston.

Both ends flanged: k = 0.850
One end flanged, one end free: k = 0.732
Both ends free: k = 0.614

Normally, k = 0.732 is assumed




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