# 4th Order Bandpass Subwoofer Box Equations Formulas Design Calculator

## Low Frequency Enclosures - Car Audio - Home Theater Sound System

Subwoofer Box Comparison Calculator:
Compare bandpass, sealed and vented frequency output graphs
for a subwoofer in one program.

Solving for sealed rear chamber Q.

note:
 for S=0.7 use b=0.7206 for S=0.6 use b=0.9560 for S=0.5 use b=1.2712

Inputs:
 front chamber port tuning frequency (fb) hertz1/day1/hour1/minute1/secondcycle/daycycle/hourcycle/minutecycle/secondrevolution/dayrevolution/hourrevolution/minuterevolution/secondrotation/dayrotation/hourrotation/minuterotation/secondRPM
 speaker total Q (Qts)
 speaker resonance frequency (fs) hertz1/day1/hour1/minute1/secondcycle/daycycle/hourcycle/minutecycle/secondrevolution/dayrevolution/hourrevolution/minuterevolution/secondrotation/dayrotation/hourrotation/minuterotation/secondRPM

#### Conversions:

 front chamber port tuning frequency (fb)= 0 = 0hertz
 speaker total Q (Qts)= 0 = 0
 speaker resonance frequency (fs)= 0 = 0hertz

#### Solution:

 sealed rear chamber Q (Qbp)= NOT CALCULATED

#### Other Units:

Change Equation
Select to solve for a different unknown
Fourth Order Bandpass
sealed rear chamber Q
 sealed rear chamber Q passband ripple sensitivity gain

low frequency f3 rolloff
 low frequency f3 rolloff speaker resonance frequency speaker total Q

high frequency f3 rolloff
 high frequency f3 rolloff low frequency f3 rolloff speaker resonance frequency speaker total Q

front chamber port tuning frequency
 front chamber port tuning frequency sealed rear chamber Q speaker resonance frequency speaker total Q

ported front chamber net volume
 ported front chamber net volume overall bandwidth speaker total Q equivalent air compliance

sealed rear chamber net volume
 sealed rear chamber net volume equivalent air compliance sealed rear chamber Q speaker total Q

maximum air volume displaced by cone excursion
 maximum air volume displaced by cone excursion cone effective radiation area cone peak linear displacement

 cone effective radiation area cone diameter plus one third of surround

port or vent length
 port or vent length volume of enclosure or box tuning frequency end correction factor

minimum port or vent diameter
 minimum port or vent diameter maximum air volume displaced by cone excursion tuning frequency

References - Books:
1) Dickason, Vance. 1991. The Loudspeaker Design Cookbook. Audio Amateur Press. 4th ed.
2) Steele, Brian. 2002. The Subwoofer DIY Page v1.1. http://www.diysubwoofers.org.

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By Jimmy Raymond

Contact: aj@ajdesigner.com