ATH-R50x vs ATH-R70X: which needs more amplifier?

The Audio-Technica ATH-R50x is 50Ω at 93.3 dB/mW; the Audio-Technica ATH-R70X is 470Ω at 98.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.

The ATH-R50x needs 4.7 dB more than the ATH-R70X to reach the same loudness — 4.7 mW against 1.6 mW.

The numbers that decide it

SpecificationATH-R50xATH-R70X
Impedance50 Ω470 Ω
Sensitivity93.3 dB/mW98.0 dB/mW
Sensitivity (voltage)106.3 dB/V101.3 dB/V
Power for 100 dB4.7 mW1.6 mW
Voltage for 100 dB0.48 V0.86 V
Current for 100 dB9.7 mA1.8 mA
Highest source impedance
that leaves them alone (one-eighth rule)
6.25 Ω58.75 Ω
Sources that reach 100 dB
out of 280
280277

Where the two part company

3 of the 280 sources have the power for the ATH-R50x but not for the ATH-R70X — Apple USB-C dongle (EU), Steinberg UR22C, Sony NW-A306.

32 sources are low enough in output impedance for the ATH-R70X under the one-eighth rule but not for the ATH-R50x (Zoom AMS-22, Audient EVO 4, ART HeadAmp 4 Pro, 29 more).

277 of the 280 sources here reach 100 dB on both.

What each one needs from 80 to 105 dB

The ATH-R70X is more demanding than 96% of the 567 non-electrostatic models in this database; the ATH-R50x than 86%.

dB SPLATH-R50x powerATH-R50x voltageATH-R70X powerATH-R70X voltage
800.05 mW48 mV0.02 mW86 mV
850.15 mW86 mV0.05 mW0.15 V
900.47 mW0.15 V0.16 mW0.27 V
951.5 mW0.27 V0.50 mW0.49 V
1004.7 mW0.48 V1.6 mW0.86 V
10515 mW0.86 V5.0 mW1.53 V

The cheapest source that satisfies both

SourcePriceHeadroom, ATH-R50xHeadroom, ATH-R70XOutput impedanceNoise
JadeAudio JA11$206.1 dB1.1 dB0.5 Ω1.7 µV
FiiO KA11$2914.4 dB9.5 dB0.7 Ω1.7 µV
FiiO BTR11$366.1 dB0.8 dB0.5 Ω8.0 µV

Of the 280 sources here, 277 reach 100 dB on both. 70 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 70 is the JadeAudio JA11, at $20. It leaves 6.1 dB of headroom on the ATH-R50x and 1.1 dB on the ATH-R70X, its output impedance is 0.5 Ω against a one-eighth limit of 6.25 Ω and 58.75 Ω, and its noise figure puts the hiss floor 29 dB and 34 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.

Try any other source.

What each sheet prints, and what it is worth

ModelAs printedToleranceStandard
ATH-R50x5 to 40,000 Hznot printednot printed
ATH-R70X5 - 40,000 Hznot printednot printed

Audio-Technica prints 5 to 40,000 Hz for the ATH-R50x and 5 - 40,000 Hz for the ATH-R70X.

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 pages in full

Both have a page of their own. In full: Audio-Technica ATH-R50x and Audio-Technica ATH-R70X. Every figure on this page comes from what Audio-Technica published, or is derived from it — what that maker publishes, counted.

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