Between the ATH-R70xa and HD 660S2, the ATH-R70xa comes out ahead in weight and driver size, while the HD 660S2 wins on several specs. Overall, the ATH-R70xa scores 66.2 and the HD 660S2 scores 64.2 on our Mars Score.
Which should you buy?
These two are nearly even on the Mars Score (66.2 vs 64.2). The decision isn't about overall quality — both clear the bar — it's about which specific trade-offs fit your use.
Pick the ATH-R70xa if you carry the device everywhere and weight or thickness has been the deciding factor before. The biggest gaps in its favor are weight, driver size.
The HD 660S2 similarly doesn't carry a headline advantage on the popular specs — look at the full table for category-specific deltas.
Both ship with comparable battery life, active noise cancellation, spatial audio, so those specs don't separate the two — focus on the differences below.
Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity tells you both are well-rounded; the differences are about trade-offs, not quality.
Why Audio-Technica - ATH-R70xa wins
- ▲Weight — 50.00 g less. 210 vs 260.
- ▲Driver size — 7.14% more. 45 mm vs 42 mm.
Why Sennheiser - HD 660S2 wins
- No decisive advantages.
Spec comparison
Design
| Spec | Audio-Technica - ATH-R70xa | Sennheiser - HD 660S2 |
|---|---|---|
| Type | over-ear | over-ear |
| Weight | 210 glead | 260 g |
| Water resistance | none | none |
Audio
| Spec | Audio-Technica - ATH-R70xa | Sennheiser - HD 660S2 |
|---|---|---|
| Driver sizeⓘ | 45 mmlead | 42 mm |
| Impedanceⓘ | 470 Ωlead | 300 Ω |
| Sensitivityⓘ | 99 dB | 104 dBlead |
| Active noise cancellationⓘ | false | false |
| Transparency mode | false | false |
| Spatial audioⓘ | false | false |
Battery
| Spec | Audio-Technica - ATH-R70xa | Sennheiser - HD 660S2 |
|---|---|---|
| Battery life | 0 h | 0 h |
| Fast chargeⓘ | false | false |
Connectivity
| Spec | Audio-Technica - ATH-R70xa | Sennheiser - HD 660S2 |
|---|---|---|
| Bluetoothⓘ | 0 | 0 |
| Multipointⓘ | false | false |
| 3.5mm jack | true | true |
| LDACⓘ | false | false |
| aptX HDⓘ | false | false |
Frequently asked
Which has better battery life, ATH-R70xa or HD 660S2?+
HD 660S2 lasts 0 hours vs 0 hours.
Do ATH-R70xa or HD 660S2 have active noise cancellation?+
Neither model has ANC.
Which supports LDAC, ATH-R70xa or HD 660S2?+
Neither supports LDAC.
Spec-level deep dives
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