The Westone MACH 20 is 96Ω at 110.0 dB (no reference unit printed); the Westone Pro X10 is 19Ω at 114.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The MACH 20 needs 4.0 dB more than the Pro X10 to reach the same loudness — 0.10 mW against 0.04 mW.
| Specification | MACH 20 | Pro X10 |
|---|---|---|
| Impedance | 96 Ω | 19 Ω |
| Sensitivity | 110.0 dB | 114.0 dB/mW |
| Sensitivity (voltage) | 120.2 dB/V | 131.2 dB/V |
| Power for 100 dB | 0.10 mW | 0.04 mW |
| Voltage for 100 dB | 98 mV | 28 mV |
| Current for 100 dB | 1.0 mA | 1.4 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 12.00 Ω | 2.38 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
One caution before reading the rows. Westone MACH 20 printed a decibel figure with no reference unit, so this page reads it as per milliwatt. If it is really per volt, that model needs far more than the table says. Why the two readings differ by so much.
Every source in the database that drives one of them drives the other. On power, the choice between these two changes nothing about what amplifier you need.
17 sources are low enough in output impedance for the MACH 20 under the one-eighth rule but not for the Pro X10 (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 14 more).
31 sources stay below the audible-hiss threshold with the MACH 20 but cross it with the Pro X10 (Kiwi Ears Allegro Mini, FiiO BTR11, Fosi Audio SK02, 28 more).
280 of the 280 sources here reach 100 dB on both.
The MACH 20 is more demanding than 31% of the 567 non-electrostatic models in this database; the Pro X10 than 2%.
| dB SPL | MACH 20 power | MACH 20 voltage | Pro X10 power | Pro X10 voltage |
|---|---|---|---|---|
| 80 | 1.0 µW | 10 mV | 0.4 µW | 3 mV |
| 85 | 3.2 µW | 17 mV | 1.3 µW | 5 mV |
| 90 | 0.01 mW | 31 mV | 4.0 µW | 9 mV |
| 95 | 0.03 mW | 55 mV | 0.01 mW | 15 mV |
| 100 | 0.10 mW | 98 mV | 0.04 mW | 28 mV |
| 105 | 0.32 mW | 0.17 V | 0.13 mW | 49 mV |
| Source | Price | Headroom, MACH 20 | Headroom, Pro X10 | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 20.0 dB | 26.5 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 28.3 dB | 37.6 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 25.2 dB | 34.5 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 42 of them also publish an output impedance low enough for both under the one-eighth rule and a noise figure that stays below the audible-hiss threshold with both.
The cheapest of the 42 is the JadeAudio JA11, at $20. It leaves 20.0 dB of headroom on the MACH 20 and 26.5 dB on the Pro X10, its output impedance is 0.5 Ω against a one-eighth limit of 12.00 Ω and 2.38 Ω, and its noise figure puts the hiss floor 15 dB and 4 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| MACH 20 | 20Hz – 18kHz | not printed | not printed |
| Pro X10 | 20Hz - 16kHz | not printed | not printed |
Westone prints 20Hz – 18kHz for the MACH 20 and 20Hz - 16kHz for the Pro X10.
Pro X10: The figure stands on Westone’s own spec sheet, not on the product page, which prints no frequency row at all.
Neither range has a tolerance printed beside it, so a wider range on one sheet is not deeper bass or more treble.
Not a measurement; maker by maker.
Both have a page of their own. In full: Westone MACH 20 and Westone Pro X10. Each figure on this page is labelled on those pages with where it came from, including the ones Westone never published — what that maker publishes, counted.