Neodymium Magnet
Superior flux density with contained mass. Force reserves at the gap that remain stable even when the voice coil exceeds 150 °C.
Article 02
Motor Thermal Design
Energy that does not become sound becomes heat. And heat decides how long a speaker remains itself.
The Real Problem
The rated power doesn't tell the full story.
When an amplifier delivers a hundred watts to a speaker, a portion of those watts becomes acoustic pressure and the vast majority becomes heat in the voice coil. That is the physics.
The real design of a speaker motor is not the maximum power survivable for an instant, but the power the system can dissipate for hours without parameters shifting.
Gap flux density
Same magnet volume: neodymium delivers a stronger field, reducing total moving mass and increasing force reserve at the gap.
Design Pillars
What this article is built on
Pole-Piece Ventilation
Calibrated slots in the central pole channel airflow behind the voice coil on each excursion. Dissipation shifts from conductive only to active convective.
Voice-Coil Former
Anodised aluminium where maximum dissipation is needed, Kapton where acoustic transparency is required. Every driver has an explicit, not accidental, trade-off.
Documented Thermal Cycles
Every new motor undergoes 96 hours of full-power pink noise. If Thiele/Small parameters drift by more than 5%, it does not pass.
Power Compression
Power compression is the loss of efficiency when the voice coil heats up. It is measured in dB and tells how much dynamics the system is losing over time. For us it is a published parameter, not a hidden one.
What This Means In-Car
In a summer cabin, an audio system may operate for hours with ambient temperatures above 50 °C. A poorly dimensioned motor loses six or seven decibels in an afternoon. A well-designed motor loses less than two.
Measured Datum
<2dB
Power compression at 1 hour @ 80% rated
Measured on MS-X10 with neodymium magnet and ventilated pole, 25 °C ambient.
“A speaker is not judged in the first three seconds. It is judged after three hours.”
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