The Letshuoer Mystic 8 is 18Ω at 107.0 dB (no reference unit printed); the Letshuoer S12 Pro is 16Ω at 102.0 dB/mW. This page is only about what they ask of an amplifier — not how they sound, which no specification on either sheet can tell you.
The S12 Pro needs 5.0 dB more than the Mystic 8 to reach the same loudness — 0.63 mW against 0.20 mW.
| Specification | Mystic 8 | S12 Pro |
|---|---|---|
| Impedance | 18 Ω | 16 Ω |
| Sensitivity | 107.0 dB | 102.0 dB/mW |
| Sensitivity (voltage) | 124.4 dB/V | 120.0 dB/V |
| Power for 100 dB | 0.20 mW | 0.63 mW |
| Voltage for 100 dB | 60 mV | 0.10 V |
| Current for 100 dB | 3.3 mA | 6.3 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 2.25 Ω | 2.00 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
One caution before reading the rows. Letshuoer Mystic 8 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.
9 sources stay below the audible-hiss threshold with the S12 Pro but cross it with the Mystic 8 (FiiO BTR11, FiiO K11 R2R, Lake People G103-S Mk II, 6 more).
280 of the 280 sources here reach 100 dB on both. That count is about power only — the output-impedance and hiss lines above are separate questions, and a source can pass this one and fail those.
The gap between these two in decibels does not change with volume — it is a property of the two headphones. What changes is the size of the numbers, and it changes fast: every 10 dB costs ten times the power. The row that matters is the one nearest the level you listen at, and for most people that is nearer the top of this table than the bottom.
The S12 Pro is more demanding than 33% of the 567 non-electrostatic models in this database; the Mystic 8 than 17%. Both figures use the same measure as the rest of the site: whichever runs out first against a 2 V, 100 mW dongle, voltage or power.
| dB SPL | Mystic 8 power | Mystic 8 voltage | S12 Pro power | S12 Pro voltage |
|---|---|---|---|---|
| 80 | 2.0 µW | 6 mV | 6.3 µW | 10 mV |
| 85 | 6.3 µW | 11 mV | 0.02 mW | 18 mV |
| 90 | 0.02 mW | 19 mV | 0.06 mW | 32 mV |
| 95 | 0.06 mW | 34 mV | 0.20 mW | 57 mV |
| 100 | 0.20 mW | 60 mV | 0.63 mW | 0.10 V |
| 105 | 0.63 mW | 0.11 V | 2.0 mW | 0.18 V |
105 dB is included because forum power figures are usually quoted there or higher. It is also a level that damages hearing in minutes — how many minutes is its own calculator.
| Source | Price | Headroom, Mystic 8 | Headroom, S12 Pro | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 19.3 dB | 13.8 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 30.7 dB | 25.9 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 27.6 dB | 22.8 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. That is the easy axis. 62 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 rest either fail one of those or never printed the number at all, and 208 of them are in the second group.
The cheapest of the 62 is the JadeAudio JA11, at $20. It leaves 19.3 dB of headroom on the Mystic 8 and 13.8 dB on the S12 Pro, its output impedance is 0.5 Ω against a one-eighth limit of 2.25 Ω and 2.00 Ω, and its noise figure puts the hiss floor 11 dB and 15 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
Cheapest that satisfies three published numbers is not the same as best, and none of it is about how either headphone sounds. To put either model against a source this page does not mention, or to change the target loudness, use the amplifier matcher.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| Mystic 8 | nothing printed | — | — |
| S12 Pro | nothing printed | — | — |
Letshuoer prints the same thing for both the Mystic 8 and the S12 Pro: nothing at all.
There is nothing here to compare, and that is worth saying plainly rather than filling the gap with somebody else’s measurement. Of the 578 models checked against a maker document so far, 490 carry a printed range and only 58 of those print the ±dB tolerance that would make a range mean anything.
None of this is a measurement. What each maker publishes, and what it is worth, is set out in the frequency response audit.
Each model has a page of its own with the full source list, the hiss estimate and the provenance of every figure above: Letshuoer Mystic 8 and Letshuoer S12 Pro. Each figure on this page is labelled on those pages with where it came from, including the ones Letshuoer never published — what that maker publishes, counted.