SOURCE 05 · TESTING · 05 / 17
IEM Driver Testing & Optimisation
Frequency response, impedance, distortion, compression and controlled listening are the evidence loop behind a dependable IEM.
5.1 Frequency-response measurement
Frequency response maps output across frequency under stated conditions. Impedance can expose resonance, vent effects and source sensitivity.
5.2 Impedance-curve analysis
THD and intermodulation become useful when frequency, level and fit are stated. A single number cannot describe a driver at every frequency and loudness.
5.3 THD and IMD measurement
Heat, mesh, glue, vent and assembly can shift output. Optimisation means finding sound that survives across samples, not perfecting one prototype.
5.4 Power compression and production variation
Level-matched reference tracks test bass control, vocal clarity, treble texture and imaging. Each session should answer a question, not collect vague praise.
5.5 Subjective listening evaluation
A driver can change output as its coil warms. Testing at realistic level and duration prevents a prototype from sounding different after extended listening.