HLMS™ High-Linearity Motor Structure

In high-end loudspeaker design, motor linearity sets the ceiling for sound quality. SOVOX High-Linearity Motor Structure™ is a dual-demodulation, high-stability motor system built on decades of coaxial and high-performance driver engineering. It reduces distortion at the source — in the magnetic circuit itself — rather than relying on correction downstream.

The problem: flux modulation

In any moving-coil motor, the signal current flowing through the voice coil generates its own magnetic field, and that field pushes against the fixed flux in the magnetic gap. The gap flux therefore rises and falls with the music itself, which makes the motor’s force factor vary with both drive level and cone position. The distortion this creates is generated inside the motor — it appears at the source of the driver’s force, before the cone, the suspension or any downstream correction can act, and it grows exactly when the driver is working hardest.

The HLMS™ answer: stabilise the flux

High-Linearity Motor Structure™ attacks the cause rather than the symptom. Two demodulation paths built into the magnetic circuit counteract the field generated by the voice-coil current, holding the gap flux constant across the coil’s full excursion. With flux stabilised, drive force stays proportional to signal current at any level and any cone position — the motor behaves linearly where a conventional motor progressively distorts. Distortion is reduced at the source of the magnetic circuit rather than corrected downstream, which is why HLMS™ drivers keep their clarity and control at high output instead of hardening as the level rises.

By SOVOX Engineering · Last updated: July 23, 2026