Balanced Mode Radiator (BMR)

A BMR is a drive unit that uses a superposition of the piston mode and bending modes to evenly distribute sound energy into an environment even at the highest frequencies.

Bending Waves (or flexural waves)

Mechanical waves that travel in solid structures (usually beams and plates) where the direction of deflection is perpendicular to the direction of propagation, thus stimulating the surrounding air.

Bending Wave Modes

By confining the bending waves to structures of a finite size a standing wave (or mode) is generated at a particular frequency of oscillation that coincides with the time taken for the wave to bounce back off of one of the boundaries.

Distributed Mode Loudspeaker (DML)

Through careful selection of plate material, geometry, boundary conditions and excitation point(s) it is possible to evenly distribute the bending wave modes across the desired frequency range. This ensures a smooth frequency response spanning over seven octaves producing extremely wide and predominantly diffuse sound coverage. This is the essence of a DML.

Driver or Drive Unit

Commonly used term for the transducer that generates sound in a loudspeaker product. For example a typical two-way loudspeaker uses two drive units; a bass-midrange driver and a tweeter.


A transducer that converts electrical energy into mechanical vibrations of whichever surface the exciter is attached to.


A device that turns one kind of energy into another. Specifically for Tectonic’s audio products this means converting electrical energy into mechanical vibrations of a diaphragm which couples this energy into the surrounding air as acoustic radiation.