The HiFiMAN HE-6se V2 is 50Ω at 83.5 dB (no reference unit printed); the HiFiMAN HE-R9 is 60Ω at 100.0 dB (no reference unit printed). This page covers what they ask of an amplifier, not how they sound.
The HE-6se V2 needs 16.5 dB more than the HE-R9 to reach the same loudness — 45 mW against 1.0 mW.
| Specification | HE-6se V2 | HE-R9 |
|---|---|---|
| Impedance | 50 Ω | 60 Ω |
| Sensitivity | 83.5 dB | 100.0 dB |
| Sensitivity (voltage) | 96.5 dB/V | 112.2 dB/V |
| Power for 100 dB | 45 mW | 1.0 mW |
| Voltage for 100 dB | 1.49 V | 0.24 V |
| Current for 100 dB | 29.9 mA | 4.1 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 6.25 Ω | 7.50 Ω |
| Sources that reach 100 dB out of 280 | 240 | 280 |
One caution before reading the rows. HiFiMAN HE-6se V2 and HiFiMAN HE-R9 printed a decibel figure with no reference unit, so this page reads it as per milliwatt. If it is really per volt, each of them needs far more than the table says. Why the two readings differ by so much.
40 of the 280 sources have the power for the HE-R9 but not for the HE-6se V2 — Apple USB-C dongle (US), Apple USB-C dongle (EU), Generic CX31993 dongles, 37 more.
1 source stays below the audible-hiss threshold with the HE-6se V2 but crosses it with the HE-R9 (Schiit Mjolnir 3).
240 of the 280 sources here reach 100 dB on both.
The HE-6se V2 is more demanding than 99% of the 567 non-electrostatic models in this database; the HE-R9 than 66%.
| dB SPL | HE-6se V2 power | HE-6se V2 voltage | HE-R9 power | HE-R9 voltage |
|---|---|---|---|---|
| 80 | 0.45 mW | 0.15 V | 0.01 mW | 24 mV |
| 85 | 1.4 mW | 0.27 V | 0.03 mW | 44 mV |
| 90 | 4.5 mW | 0.47 V | 0.10 mW | 77 mV |
| 95 | 14 mW | 0.84 V | 0.32 mW | 0.14 V |
| 100 | 45 mW | 1.49 V | 1.0 mW | 0.24 V |
| 105 | 141 mW | 2.66 V | 3.2 mW | 0.44 V |
| Source | Price | Headroom, HE-6se V2 | Headroom, HE-R9 | Output impedance | Noise |
|---|---|---|---|---|---|
| FiiO KA11 | $29 | 4.6 dB | 20.3 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 1.5 dB | 17.2 dB | 0.6 Ω | 1.0 µV |
| iBasso DC03 Pro | $69 | 1.5 dB | 17.2 dB | 0.12 Ω | 0.9 µV |
Of the 280 sources here, 240 reach 100 dB on both. 66 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 66 is the FiiO KA11, at $29. It leaves 4.6 dB of headroom on the HE-6se V2 and 20.3 dB on the HE-R9, its output impedance is 0.7 Ω against a one-eighth limit of 6.25 Ω and 7.50 Ω, and its noise figure puts the hiss floor 39 dB and 23 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| HE-6se V2 | 8Hz- 65 KHz | not printed | not printed |
| HE-R9 | 15Hz-35kHz | not printed | not printed |
HiFiMAN prints 8Hz- 65 KHz for the HE-6se V2 and 15Hz-35kHz for the HE-R9.
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: HiFiMAN HE-6se V2 and HiFiMAN HE-R9. Each figure on this page is labelled on those pages with where it came from, including the ones HiFiMAN never published — what that maker publishes, counted.