Audio-Technica - ATH-R70xa vs Sennheiser - HD 660S2

The ATH-R70xa edges ahead on the Mars Score (66.2 vs 61.4), but the 4.8-point gap is small enough that the right pick comes down to which spec advantages matter to you.

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.