Max SPL and excursion calculator
Set amplifier voltage and box volume and see excursion, sound pressure and power at 40 Hz. If excursion exceeds Xmax it turns red – the driver then distorts strongly or gets damaged.
Try it free in the app
Excursion limits the level
In the bass it is usually not power but excursion (Xmax) that sets the limit. The calculator uses the complete driver impedance including the back-effect of the box spring.
What the app adds
Max SPL over the whole frequency range, port air velocity, thermal compression and required amplifier power.
Frequently asked questions
What is Xmax?
The linear travel of the voice coil (in one direction). Beyond it distortion rises sharply.
Why does excursion rise in larger boxes?
The box acts like a spring supporting the driver. A larger volume is softer – excursion at the same voltage grows.
How accurate is the value?
It is a simple model (half space, no distortion). The app calculates more precisely.