Sealed Enclosure Alignment
Canonical Definition
A sealed alignment is the combined driver, trapped-air compliance, source resistance, leakage, absorption, panel behavior, filtering, and acoustic-load system. Qtc and Fc describe an idealized low-level state; they do not by themselves prove subjective transient quality or installed response.
Ideal Starting Equations
Vb = Vas / ((Qtc / Qts)^2 - 1)
Fc = Fs × (Qtc / Qts)These equations are useful only when the linear driver parameters and ideal closed-box assumptions are appropriate. Series resistance, leakage, stuffing, suspension creep, temperature, panel motion, EQ, and the vehicle can move the result.
Qtc Is A Response Descriptor
| Change | Typical ideal-model effect | What must still be measured |
|---|---|---|
| Smaller net volume | Higher Fc and Qtc | magnitude, group delay, excursion, compression |
| Larger net volume | Lower Fc and Qtc | mechanical margin and EQ demand |
| More series resistance | Reduced electrical damping and higher system Q | actual amplifier, wire, and connection loss |
| Damping material | changes absorption and apparent compliance | density, placement, impedance, leakage, output |
Descriptions such as “tight,” “slow,” or “boomy” also depend on room or cabin response, group delay, level, distortion, crossover, and program material.
Net Volume And Construction
Start from internal gross volume, then subtract driver, bracing, terminals, inserts, and other solids. Record gasket compression, wall flex, fill type and mass, and every leak. Complex printed enclosures should use CAD volume properties and an as-built check.
Verification
- Measure the driver at a documented cool state.
- Verify actual net air volume and construction displacement.
- Measure low-level impedance and fit Fc, Qtc, and losses.
- Measure near-field acoustic response and leak noise.
- Model and verify excursion and compression with any boost or protective filter.
- Measure the installed transfer at the intended seats.