Bandpass Designer Sealed Designer Vented Designer
Instructions:
Bandpass Sealed Vented Example
Box Calculator (Windows):
Bandpass Sealed Vented

Subwoofer Box Comparison Calculator:
Flash version of all three calculators (Bandpass, Sealed and Vented)

# Bandpass Instructions

Bandpass Designer Software calculates 4th order bandpass theoretical enclosures and boxes.

## Input Parameters:

The following Theile Small speaker parameters are required for input. These values should be included with your speaker manual or can be found on the manufacturer's web site.
• Qts: Total Q of the speaker
• Qes: Speaker electrical Q
• Fs: Free air resonance of speaker in Hz
• Vas: Volume of air equal to the speakers spring characteristics in liters
• Pmax: Maximum power of the driver in watts
• Diameter: The diameter of the driver in cm
• Xmax: The amount of cone movement in one direction in mm
• Dp: Diameter of the port(s) in cm
• # Ports: Number of ports
The following speaker parameters are user defined inputs. These values should be chosen by user preference.
• Gain: dB increase of the system
• S: Ripple
S = 0.5 - Degraded response pronounced ripple
S = 0.6 - Slightly degraded response slight ripple
S = 0.7 - Best transient response no ripple
Notes:
• MAKE SURE THE UNITS MATCH (e.g. Vas is in liters not cubic feet).
• Pmax, Diameter, and Xmax are not required for box calculation. They are used to determine the power response curve. Vf, Vr, Fl, Fh, Fb, and Lp will still be valid for Qts, Qes, Vas, Dp and number of Ports.
• Ported designs require tuning. Bandpass Designer should give a good approximation of box parameters for most applications.
• Use the largest diameter port as the design allows. Drivers greater than 10" in diameter can produce port noise due to the air movement.

## Calculated/Output Parameters:

The following speaker box and enclosure parameters are calculated:
• Vf: Internal volume of front chamber (port goes into this chamber) in liters.
• Vr: Internal volume of rear chamber (sealed) in liters.
• Fb: Box resonance in Hz
• Fl: -3 dB frequency for the low end roll off
• Fh: -3 dB frequency for the high end roll off
• Lp: Length of port(s) in cm
Notes:
• Fl is an important parameter. The lower the Fl the deeper the bass. A Fl below 50 Hz should be suitable.
• Vb is the volume of the box. Generally, the lower the bass the bigger the box.
• For Box Calculator instructions go here.

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By Jimmy Raymond

Contact: aj@ajdesigner.com