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Qtc Equation:
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The Qtc equation calculates the total Q factor for sealed subwoofer enclosure design. It relates the driver's Q (Qts), compliance volume (Vas), and box volume (Vb) to determine the system's overall Q factor when installed in an enclosure.
The calculator uses the Qtc equation:
Where:
Explanation: The equation shows how the enclosure volume affects the overall Q factor of the subwoofer system, with smaller boxes resulting in higher Qtc values.
Details: Qtc is crucial for sealed subwoofer design as it determines the system's frequency response, transient response, and overall sound quality. Different Qtc values produce different bass characteristics.
Tips: Enter Qts (typically 0.2-0.7), Vas in liters, and Vb in liters. All values must be positive numbers. The calculator will compute the resulting Qtc for your sealed enclosure design.
Q1: What is a good Qtc value for subwoofers?
A: Qtc values around 0.707 provide the flattest response (Butterworth alignment). Lower Qtc (0.5-0.6) gives tighter bass, higher Qtc (0.8-1.0) provides more output but less controlled bass.
Q2: How does box volume affect Qtc?
A: Larger boxes result in lower Qtc values (closer to driver's Qts), while smaller boxes increase Qtc. The relationship follows the inverse square root function shown in the equation.
Q3: What's the difference between Qts and Qtc?
A: Qts is the driver's inherent Q factor in free air, while Qtc is the system Q factor when the driver is mounted in an enclosure.
Q4: Can this equation be used for ported boxes?
A: No, this equation is specifically for sealed enclosures. Ported boxes have different alignment equations and considerations.
Q5: How accurate is this calculation?
A: The equation provides a good theoretical approximation, but actual results may vary slightly due to factors like box construction, stuffing, and driver variations.