ATH-R70X vs ATH-R70xa: which needs more amplifier?

The Audio-Technica ATH-R70X is 470Ω at 98.0 dB/mW; the Audio-Technica ATH-R70xa is 470Ω at 97.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.

The ATH-R70xa needs 1.0 dB more than the ATH-R70X to reach the same loudness — 2.0 mW against 1.6 mW.

The numbers that decide it

SpecificationATH-R70XATH-R70xa
Impedance470 Ω470 Ω
Sensitivity98.0 dB/mW97.0 dB/mW
Sensitivity (voltage)101.3 dB/V100.3 dB/V
Power for 100 dB1.6 mW2.0 mW
Voltage for 100 dB0.86 V0.97 V
Current for 100 dB1.8 mA2.1 mA
Highest source impedance
that leaves them alone (one-eighth rule)
58.75 Ω58.75 Ω
Sources that reach 100 dB
out of 280
277275

Where the two part company

2 of the 280 sources have the power for the ATH-R70X but not for the ATH-R70xa — FiiO BTR11, Sony NW-ZX707.

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

What each one needs from 80 to 105 dB

The ATH-R70xa is more demanding than 98% of the 567 non-electrostatic models in this database; the ATH-R70X than 96%.

dB SPLATH-R70X powerATH-R70X voltageATH-R70xa powerATH-R70xa voltage
800.02 mW86 mV0.02 mW97 mV
850.05 mW0.15 V0.06 mW0.17 V
900.16 mW0.27 V0.20 mW0.31 V
950.50 mW0.49 V0.63 mW0.54 V
1001.6 mW0.86 V2.0 mW0.97 V
1055.0 mW1.53 V6.3 mW1.72 V

The cheapest source that satisfies both

SourcePriceHeadroom, ATH-R70XHeadroom, ATH-R70xaOutput impedanceNoise
JadeAudio JA11$201.1 dB0.1 dB0.5 Ω1.7 µV
FiiO KA11$299.5 dB8.5 dB0.7 Ω1.7 µV
FiiO BTR13$596.1 dB5.1 dB0.6 Ω1.0 µV

Of the 280 sources here, 275 reach 100 dB on both. 71 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 71 is the JadeAudio JA11, at $20. It leaves 1.1 dB of headroom on the ATH-R70X and 0.1 dB on the ATH-R70xa, its output impedance is 0.5 Ω against a one-eighth limit of 58.75 Ω for both, and its noise figure puts the hiss floor 34 dB and 35 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-R70X5 - 40,000 Hznot printednot printed
ATH-R70xa5 to 40,000 Hznot printednot printed

Audio-Technica prints 5 - 40,000 Hz for the ATH-R70X and 5 to 40,000 Hz for the ATH-R70xa.

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-R70X and Audio-Technica ATH-R70xa. 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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