The Audio-Technica ATH-AD700X is 38Ω at 100.0 dB/mW; the Audio-Technica ATH-R70xa is 470Ω at 97.0 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 ATH-R70xa needs 3.0 dB more than the ATH-AD700X to reach the same loudness — 2.0 mW against 1.0 mW.
| Specification | ATH-AD700X | ATH-R70xa |
|---|---|---|
| Impedance | 38 Ω | 470 Ω |
| Sensitivity | 100.0 dB/mW | 97.0 dB/mW |
| Sensitivity (voltage) | 114.2 dB/V | 100.3 dB/V |
| Power for 100 dB | 1.0 mW | 2.0 mW |
| Voltage for 100 dB | 0.19 V | 0.97 V |
| Current for 100 dB | 5.1 mA | 2.1 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 4.75 Ω | 58.75 Ω |
| Sources that reach 100 dB out of 280 | 280 | 275 |
5 of the 280 sources have the power for the ATH-AD700X but not for the ATH-R70xa — Apple USB-C dongle (EU), FiiO BTR11, Steinberg UR22C, 2 more.
32 sources are low enough in output impedance for the ATH-R70xa under the one-eighth rule but not for the ATH-AD700X (Zoom AMS-22, Audient EVO 4, ART HeadAmp 4 Pro, 29 more).
1 source stays below the audible-hiss threshold with the ATH-R70xa but crosses it with the ATH-AD700X (Schiit Mjolnir 3).
275 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 ATH-R70xa is more demanding than 98% of the 567 non-electrostatic models in this database; the ATH-AD700X than 57%. 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 | ATH-AD700X power | ATH-AD700X voltage | ATH-R70xa power | ATH-R70xa voltage |
|---|---|---|---|---|
| 80 | 0.01 mW | 19 mV | 0.02 mW | 97 mV |
| 85 | 0.03 mW | 35 mV | 0.06 mW | 0.17 V |
| 90 | 0.10 mW | 62 mV | 0.20 mW | 0.31 V |
| 95 | 0.32 mW | 0.11 V | 0.63 mW | 0.54 V |
| 100 | 1.0 mW | 0.19 V | 2.0 mW | 0.97 V |
| 105 | 3.2 mW | 0.35 V | 6.3 mW | 1.72 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, ATH-AD700X | Headroom, ATH-R70xa | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 14.0 dB | 0.1 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 22.3 dB | 8.5 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 19.2 dB | 5.1 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 275 reach 100 dB on both. That is the easy axis. 68 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 204 of them are in the second group.
The cheapest of the 68 is the JadeAudio JA11, at $20. It leaves 14.0 dB of headroom on the ATH-AD700X and 0.1 dB on the ATH-R70xa, its output impedance is 0.5 Ω against a one-eighth limit of 4.75 Ω and 58.75 Ω, and its noise figure puts the hiss floor 21 dB and 35 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 |
|---|---|---|---|
| ATH-AD700X | 5 – 30,000 Hz | not printed | not printed |
| ATH-R70xa | 5 to 40,000 Hz | not printed | not printed |
Audio-Technica prints 5 – 30,000 Hz for the ATH-AD700X and 5 to 40,000 Hz for the ATH-R70xa.
Neither range has a tolerance printed beside it, and that is the whole of what this section can tell you. A wider range on one sheet is not deeper bass or more treble on that headphone: without a tolerance, neither number says how loud either model is at the ends of its own range, so the difference between the two is a difference between two pieces of marketing copy. A ±dB figure is what turns a range into a specification, and of the 490 models whose maker prints a range, 58 print it.
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: Audio-Technica ATH-AD700X 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.