The three headphone transducer types differ in how force is applied to the diaphragm, what limits their performance, and what the surrounding system must supply. Those differences are real and partly predictable. Tuning, enclosure design and implementation quality can outweigh them, so type alone does not predict how a specific model performs.
How each type drives air
Dynamic (moving-coil). A voice coil attached to the diaphragm moves in a magnetic gap. Force is applied at one point, the coil, and the diaphragm must carry it across its surface. At low frequencies it moves as a piston. At higher frequencies it develops breakup modes, which designers control through diaphragm material, geometry and damping. Moving mass includes the coil and former. The type’s strengths are high efficiency, compact size and the widest design freedom of the three.
Planar magnetic. Conductive traces on a thin film sit within a magnet array. Force is distributed across the diaphragm’s area, which reduces the point-drive breakup problem of dynamic designs. The costs are structural. The magnet array sits in the acoustic path and affects airflow and reflections, the magnets add weight, and many designs have lower sensitivity and need more amplifier power.
Electrostatic. The diaphragm carries a fixed charge set by a bias voltage and sits between two perforated stators. The signal, applied push-pull to the stators, creates a field that acts on the whole diaphragm. Nothing is attached to the film, so moving mass is very low relative to the air load. The cost is the electrical interface. The load is capacitive, so the amplifier must deliver a high-voltage swing rather than high current, and the system must also supply the bias. STAX uses a 580V bias standard in the SR-X1 + SRM-400S system, which is why a dedicated driver unit is required.
Technical comparison
| Dynamic | Planar magnetic | Electrostatic | |
|---|---|---|---|
| Force application | Point (coil) | Distributed (traces) | Distributed (field across diaphragm) |
| Moving mass | Diaphragm + coil | Diaphragm + traces | Diaphragm only |
| Electrical load | Inductive, impedance varies with frequency | Largely resistive | Capacitive |
| Amplifier demand | Usually modest | Often higher power | High-voltage swing plus bias, dedicated driver |
| Principal design challenges | Diaphragm breakup, coil nonlinearity | Magnet structure in acoustic path, weight, efficiency | Bias supply, insulation, system dependence |
| Typical use | Portable to home | Mostly home | Home |
Specifications that matter
Category does not determine these, but they are where model-to-model differences show up:
- Frequency response, with the measurement rig and compensation curve stated. Compare only measurements made on the same rig.
- Distortion (THD) at stated SPL, especially in the bass and at high levels.
- Transient behaviour: impulse or step response and decay (waterfall/CSD).
- Channel matching across the band.
- Sensitivity in the unit that fits the type (dB/mW for dynamic and planar, dB/V for electrostatic).
- Electrical load: impedance curve for dynamic and planar, capacitance for electrostatic, plus compatible drivers or amplifiers.
- Weight and clamp force, which affect real listening sessions.
[Insert SR-X1 / SRM-400S data: frequency response, THD, sensitivity, capacitance, weight, price.]
What the transducer does not determine
- Voicing. Target response is a design decision in every type, and it can swamp type-level differences.
- Acoustic design. Enclosure, venting, pads and damping shape the result as much as the driver.
- The recording and source chain.
- Test conditions. Cross-type comparisons without level matching are unreliable, since louder is routinely heard as better.
Audition method
Level-match to within a fraction of a dB, use one source chain, and switch quickly between candidates. Use material you know, chosen to stress different behaviours:
| Material | What to check |
|---|---|
| Vocal-led | Phrasing, sibilance, apparent distance |
| Dense pop or electronic | Whether individual elements stay separable at high complexity |
| Live or jazz ensemble | Spatial cues and room information |
| Rhythm-led | Bass texture and transient definition |