The Sennheiser IE 100 PRO is 20Ω at 98.0 dB/mW; the Sennheiser IE 300 is 16Ω at 106.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The IE 100 PRO needs 8.0 dB more than the IE 300 to reach the same loudness — 1.6 mW against 0.25 mW.
| Specification | IE 100 PRO | IE 300 |
|---|---|---|
| Impedance | 20 Ω | 16 Ω |
| Sensitivity | 98.0 dB/mW | 106.0 dB/mW |
| Sensitivity (voltage) | 115.0 dB/V | 124.0 dB/V |
| Power for 100 dB | 1.6 mW | 0.25 mW |
| Voltage for 100 dB | 0.18 V | 63 mV |
| Current for 100 dB | 8.9 mA | 4.0 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 2.50 Ω | 2.00 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
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.
4 sources stay below the audible-hiss threshold with the IE 100 PRO but cross it with the IE 300 (FiiO BTR11, FiiO K11 R2R, Lake People G111 Mk II, 1 more).
280 of the 280 sources here reach 100 dB on both.
The IE 100 PRO is more demanding than 52% of the 567 non-electrostatic models in this database; the IE 300 than 18%.
| dB SPL | IE 100 PRO power | IE 100 PRO voltage | IE 300 power | IE 300 voltage |
|---|---|---|---|---|
| 80 | 0.02 mW | 18 mV | 2.5 µW | 6 mV |
| 85 | 0.05 mW | 32 mV | 7.9 µW | 11 mV |
| 90 | 0.16 mW | 56 mV | 0.03 mW | 20 mV |
| 95 | 0.50 mW | 0.10 V | 0.08 mW | 36 mV |
| 100 | 1.6 mW | 0.18 V | 0.25 mW | 63 mV |
| 105 | 5.0 mW | 0.32 V | 0.79 mW | 0.11 V |
| Source | Price | Headroom, IE 100 PRO | Headroom, IE 300 | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 10.7 dB | 17.8 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 21.5 dB | 29.9 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 18.4 dB | 26.8 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 65 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 65 is the JadeAudio JA11, at $20. It leaves 10.7 dB of headroom on the IE 100 PRO and 17.8 dB on the IE 300, its output impedance is 0.5 Ω against a one-eighth limit of 2.50 Ω and 2.00 Ω, and its noise figure puts the hiss floor 20 dB and 11 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| IE 100 PRO | 20 - 18,000 Hz | not printed | not printed |
| IE 300 | 6 Hz - 20,000 Hz | not printed | not printed |
Sennheiser prints 20 - 18,000 Hz for the IE 100 PRO and 6 Hz - 20,000 Hz for the IE 300.
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: Sennheiser IE 100 PRO and Sennheiser IE 300. Every figure on this page comes from what Sennheiser published, or is derived from it — what that maker publishes, counted.