Sources, conventions & corrections

Our mathematical starting point

SubwooferTools presents original explanations built around standard lumped-parameter acoustics and loudspeaker small-signal theory. Its calculations are intended to be reproducible, with input definitions and assumptions published beside each tool.

Useful references

The original work of A. N. Thiele and Richard H. Small underpins modern low-frequency loudspeaker design. Their publications are the appropriate starting point for deeper historical and theoretical discussion.

• Janne Ahonen, Electroacoustic Modelling of the Subwoofer Enclosures, Linearteam technical paper, July 6, 2007.
• Leo Beranek and Tim Mellow, Acoustics: Sound Fields, Transducers and Vibration, Elsevier, 2019, chapters 6-7. ISBN 978-0-12-815227-0.

The editorial rule

A referenced equation is checked against its units, stated assumptions, and surrounding derivation before use. When sources use different conventions, such as one-sided versus two-sided acoustic power or RMS versus peak excursion, the calculator states which convention it uses.

Reference to a copyrighted book does not imply permission to republish its figures, tables, or passages.

Implementation and numerical boundaries

The core equations use SI units. Complex driver and enclosure models solve the coupled acoustic and electrical system before converting pressure to decibels. Frequency sweeps and reported maxima are limited to the explicitly stated sampled range.

Piston radiation uses a stable low-frequency approximation and numerical quadrature elsewhere. Measured group delay unwraps phase before differentiation and identifies the selected smoothing. Each tool publishes its model-specific limits and conventions.

Corrections improve the reference

To report a mistake, prepare a correction with the URL, your inputs and units, the result you obtained, and your expected result or measurement. We welcome corrections that make the assumptions clearer, even when the arithmetic itself is right.