ISP™ Integrated Suspension Coaxial

SOVOX secured China's first coaxial loudspeaker structure patent in 1994. The ISP — Integrated Suspension Patent — coaxial driver, with its built-in suspension architecture, is the signature result of 35 years of continuous coaxial research. High- and low-frequency units are integrated on a single axis, so sound propagates from one coincident point, for reproduction that is more natural and more accurate.

How the ISP™ architecture works

In an ISP™ coaxial driver, the high-frequency unit is mounted inside the low-frequency motor structure using the patented built-in suspension, so no bracket or post stands in front of the cone. The tweeter sits exactly at the acoustic centre of the woofer, and the woofer cone itself acts as a smooth, continuous waveguide for the high frequencies. Because both units radiate from one physical point, their wavefronts leave the driver already aligned in time — there is no path-length difference to correct in the crossover, and the alignment holds at any listening distance and at any angle. Hardware that would normally sit in the sound path, and the reflections and diffraction it causes, is simply not there.

Why a single acoustic centre is audible

With a conventional separate tweeter and woofer, the two units are centimetres apart, so their outputs arrive at slightly different times everywhere except one axis. Around the crossover region this produces lobing and response ripple that change as the listener moves — the stereo image wanders and the tonal balance shifts between sitting and standing. A true point source removes the cause instead of treating the symptom: with no inter-driver offset there is nothing to lobe, phantom images stay locked in place, and the balance you hear on axis is the balance you hear across the listening window. This is why coaxial point-source designs are favoured for nearfield studio monitoring, where the listener sits close and small head movements are unavoidable.

Where ISP™ is used

SOVOX secured China’s first coaxial loudspeaker structure patent in 1994 and has refined the architecture continuously since. Today every SOVOX coaxial driver — across the PRO, ART and ULTRA series, from 2.35" desktop formats to 12" professional units — is built on the ISP™ architecture, and it is the foundation of the MiniMax3 Monitor.

By SOVOX Engineering · Last updated: July 23, 2026