Tools
Loudspeaker design software: WinISD, VituixCAD, Hornresp, REW and more
Anyone who starts building loudspeakers soon finds that every part of the design has its own program. One for the cabinet, another for the crossover, a third for measuring. Most of them are free and they are excellent tools. Here is an overview of the most widely used ones, what they are for and how Loudsmith works alongside them.
Cabinet simulation
WinISD
A free Windows classic. It simulates sealed boxes, bass reflex, bandpass and passive radiators. It shows the frequency response, cone excursion, port air speed and group delay. For a quick estimate of a bass cabinet it is still one of the best tools around. It does not handle crossovers, lines or panel dimensions.
Hornresp
David McBean's program is free and it is the standard for anything with a horn in it: horns, back-loaded horns, transmission lines, TQWT and bandpass boxes. It is a one-dimensional simulation, so it handles waves travelling along a line or horn well. The interface is spartan and takes some learning. If you want to build a Frugel-Horn or a back-loaded horn, you will not get far without Hornresp.
Martin J. King's worksheets
Mathematical models of quarter-wave lines in MathCad. Much of today's understanding of TQWT and ML-TL comes from them. They are for non-commercial use and need a paid copy of MathCad, so these days only a small circle of people use them. The summary of his method is well worth reading, though.
Online calculators
For example the Boomspeaker calculator or the formulas at usenclosure.com. They are fine for a first estimate of volume and port length, but they only cover an ideal sealed box and bass reflex. The formulas they use are explained in Speaker box calculations step by step.
Crossover design
VituixCAD
Kimmo Saunisto's program is free (with an option to donate) and for many people the best crossover tool today. It handles passive and active multi-way systems with many drivers. It calculates off-axis radiation and power response and has its own diffraction and enclosure tools. To be meaningful it needs measured FRD and ZMA files for every driver, ideally off-axis too.
Passive Crossover Designer (Jeff Bagby)
A free Excel spreadsheet, and its successor WinPCD, which does not need Excel. A whole generation of DIY builders learnt crossover design on it. It also works with FRD and ZMA, but on-axis only.
BoxSim (Visaton)
A free German program from the driver maker Visaton. It simulates the cabinet, crossover and radiation, and has Visaton driver data built in, which makes it popular for their kits.
LspCAD
A commercial program that was long one of the standards. It is used, for example, in student theses at Brno University of Technology.
Baffle edge diffraction
The Edge from Tolvan is a small free simulator of baffle edge diffraction. It was the reference tool for a long time, but it has limits: it only models a flat baffle without cabinet depth and does not handle several drivers at once well. Today it is often replaced by the module in VituixCAD.
Measurement
REW (Room EQ Wizard)
John Mulcahy's program is free and is the standard for measuring both loudspeakers and rooms. It measures with a sweep and a measurement microphone, and with a jig also impedance and Thiele-Small parameters. Its output is FRD and ZMA files for the crossover program. It is very powerful and therefore also complex.
For a first measurement with nothing to install, Loudsmith has speaker measurement right in the browser. It measures the speaker at a distance and up close, merges them into one curve and exports an FRD. For impedance you still need REW or another program with a jig.
Where Loudsmith fits in
The classic workflow means jumping between five programs and copying parameters by hand. Loudsmith brings the whole design together in one place in the browser:
| Step | The classic way | In Loudsmith |
|---|---|---|
| Choosing drivers | datasheets, spreadsheets | a catalogue of 1,604 drivers with prices and parameters |
| Cabinet | WinISD, Hornresp | up to eight types at once, including TL, TQWT, ML-TL and open baffle |
| Crossover | VituixCAD, PCD | automatic design to an acoustic target with parts you can buy |
| Dimensions and panels | by hand, CAD | drawing, cut list, 3D model |
| Shopping | by hand | a shopping list with prices |
| Room | REW, guesswork | the room planner with modes and reflections |
| Measurement | REW | measurement in the browser, FRD back into the design |
To be honest about the limits too: Loudsmith does not simulate horns, back-loaded horns or bandpass boxes. It does not model cone breakup or off-axis radiation. Hornresp and VituixCAD are better at those. A sensible workflow is to design the speaker in Loudsmith, build it, measure it, and for a demanding project fine-tune the crossover in VituixCAD with off-axis measurements. The measured FRD can also go back into Loudsmith, which recalculates the crossover on real data.
Which program for what
- A first speaker, a quick complete design: Loudsmith.
- Just a bass cabinet or a subwoofer: WinISD or Loudsmith.
- A horn, back-loaded horn or an unusually shaped line: Hornresp.
- Fine-tuning a crossover on off-axis measurements: VituixCAD.
- Measurement and impedance: REW, or Loudsmith for a quick measurement without installing anything.
Free tools: Room planner · Speaker measurement