Martin J King Mathcad Worksheets Jun 2026

For the user, the process is remarkably simple. The primary task is to input a few key parameters on the first page of a worksheet. This includes the driver's Thiele-Small (T/S) parameters and the preliminary physical dimensions of the proposed enclosure. The Mathcad worksheet then does the heavy lifting, instantly calculating and plotting the system's predicted performance, including acoustic output and electrical impedance. Over the years, the worksheets have evolved to model increasingly complex real-world factors like baffle step response, floor reflections, and the effect of different stuffing materials and densities.

Enclosures that couple the driver's rear wave to a expanding horn profile for high-efficiency bass reinforcement.

King's revolution was to provide a repeatable, physics-based method. His models solved the one-dimensional exponential horn wave equation, merged with an empirically derived fiber damping correlation, to accurately simulate the complex interactions inside the line. The result was a tool that could predict performance with remarkable accuracy, allowing builders to iterate designs on a computer before ever cutting a piece of wood.

Tapered (TQWT), straight, or expanding lines.

This was King's most groundbreaking contribution. The worksheets feature highly accurate algorithms to model how different densities of stuffing material absorb high frequencies and artificially "lengthen" the acoustic profile of the box. Visual Outputs martin j king mathcad worksheets

Martin J. King's worksheets were originally distributed for free or a nominal fee directly through his Quarter-Wave website. Over time, changes to Mathcad's licensing, software versions, and King's retirement from active updates made running the original sheets more technically challenging for modern operating systems.

Plots the combined system response, including driver cone, port/terminus, and cabinet reflections.

Whether you prefer a or a no-compromise open baffle .

While MJK's worksheets remain a gold standard for TL design, other tools and programs have emerged. The modern DIY designer is likely to encounter: For the user, the process is remarkably simple

By watching the results change with inputs, designers gain a deeper understanding of acoustic principles, rather than just relying on a black-box simulation.

Are you trying to on a modern PC?

Various open-source developers have attempted to clone King's math into dedicated, freeware Windows applications specifically for transmission line design.

Input the speaker driver's Thiele-Small parameters ( The Mathcad worksheet then does the heavy lifting,

Martin J. King revolutionized this hobby by applying rigorous fluid dynamics and acoustic physics to these enclosures. He packaged these complex equations into a series of accessible, highly accurate Mathcad worksheets. Who is Martin J. King?

Mastering Quarter-Wave Loudspeaker Design: The Legacy of Martin J. King’s Mathcad Worksheets

They solve the equivalent acoustic and electrical circuits for the driver and enclosure, considering factors like stuffing density, driver location, and tapered geometries. Core Capabilities:

While Martin J. King has retired and no longer updates the original Mathcad files, his models remain the "gold standard" for quarter-wave theory. Many of his equations have since been ported into modern software like software or AkAbak , ensuring his contributions continue to influence speaker building today.

These sheets use advanced acoustic modeling, specifically designed for DIYers to predict frequency response and impedance curves for transmission lines, tapered transmission lines, and back-loaded horns.