Moondrop Blessing 3 vs Truthear Hexa: which needs more amplifier?

The Moondrop Blessing 3 is 14.8Ω at 101.7 dB/mW; the Truthear Hexa is 20.5Ω at 103.1 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 Moondrop Blessing 3 needs 1.4 dB more than the Truthear Hexa to reach the same loudness — 0.68 mW against 0.49 mW.

The numbers that decide it

SpecificationMoondrop Blessing 3Truthear Hexa
Impedance14.8 Ω20.5 Ω
Sensitivity101.7 dB/mW103.1 dB/mW
Sensitivity (voltage)120.0 dB/V120.0 dB/V
Power for 100 dB0.68 mW0.49 mW
Voltage for 100 dB0.10 V0.10 V
Current for 100 dB6.8 mA4.9 mA
Highest source impedance
that leaves them alone (one-eighth rule)
1.85 Ω2.56 Ω
Sources that reach 100 dB
out of 280
280280

Where the two part company

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.

3 sources are low enough in output impedance for the Truthear Hexa under the one-eighth rule but not for the Moondrop Blessing 3 (Astell&Kern HC3, RME Fireface UFX II, RME Fireface UFX III).

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.

What each one needs from 80 to 105 dB

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 Truthear Hexa is more demanding than 33% of the 567 non-electrostatic models in this database; the Moondrop Blessing 3 than 32%. 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 SPLMoondrop Blessing 3 powerMoondrop Blessing 3 voltageTruthear Hexa powerTruthear Hexa voltage
806.8 µW10 mV4.9 µW10 mV
850.02 mW18 mV0.02 mW18 mV
900.07 mW32 mV0.05 mW32 mV
950.21 mW56 mV0.15 mW56 mV
1000.68 mW0.10 V0.49 mW0.10 V
1052.1 mW0.18 V1.5 mW0.18 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.

The cheapest source that satisfies both

SourcePriceHeadroom, Moondrop Blessing 3Headroom, Truthear HexaOutput impedanceNoise
JadeAudio JA11$2013.1 dB15.9 dB0.5 Ω1.7 µV
FiiO KA11$2925.3 dB26.6 dB0.7 Ω1.7 µV
FiiO BTR11$3617.9 dB18.9 dB0.5 Ω8.0 µV

Of the 280 sources here, 280 reach 100 dB on both. That is the easy axis. 69 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 69 is the JadeAudio JA11, at $20. It leaves 13.1 dB of headroom on the Moondrop Blessing 3 and 15.9 dB on the Truthear Hexa, its output impedance is 0.5 Ω against a one-eighth limit of 1.85 Ω and 2.56 Ω, and its noise figure puts the hiss floor 15 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.

What each sheet prints, and what it is worth

ModelAs printedToleranceStandard
Moondrop Blessing 310Hz-30kHznot printednot printed
 20Hz-20kHz (IEC60318-4, -3dB)-3 dBIEC60318-4
Truthear Hexa8-40kHz (IEC61094, Free Field)not printedIEC61094 (free field)
 20-20kHz (IEC60318-4, -3dB)-3 dBIEC60318-4

Moondrop prints two ranges, “10Hz-30kHz” and “20Hz-20kHz (IEC60318-4, -3dB)”, for the Blessing 3. Truthear prints two ranges, “8-40kHz (IEC61094, Free Field)” and “20-20kHz (IEC60318-4, -3dB)”, for the Hexa.

Both sheets print a tolerance, which is rare enough to be worth pointing at: only 58 of the 490 models with a printed range do. These two ranges can be set against each other, because each of them says how far down the response is allowed to be at the ends.

None of this is a measurement. What each maker publishes, and what it is worth, is set out in the frequency response audit.

Both pages in full

Each model has a page of its own with the full source list, the hiss estimate and the provenance of every figure above: Moondrop Blessing 3 and Truthear Hexa. Every figure on this page comes from what Moondrop and Truthear published, or is derived from it — what Moondrop publishes and what Truthear publishes, both counted.

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