Between the HD 660S2 and ULT Wear 2, the HD 660S2 comes out ahead in several specs, while the ULT Wear 2 wins on driver size and weight. Overall, the HD 660S2 scores 61.4 and the ULT Wear 2 scores 70.9 on our Mars Score.
Which should you buy?
The ULT Wear 2 is the clear pick on raw spec strength, leading by 9.5 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.
The HD 660S2 doesn't pull ahead on any single popular-comparison spec — its strengths sit in the spec table groups rather than the headline advantages.
Pick the ULT Wear 2 if you carry the device everywhere and weight or thickness has been the deciding factor before. Its strongest claims are driver size, weight, active noise cancellation, among others.
Both ship with comparable spatial audio, water resistance, so those specs don't separate the two — focus on the differences below.
Bottom line: the ULT Wear 2 is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why Sennheiser - HD 660S2 wins
- No decisive advantages.
Why Sony - ULT Wear 2 wins
- ▲Driver size — 5.26% more. 40 mm vs 38 mm.
- ▲Weight — 5.00 g less. 255 vs 260.
- ▲Has Active noise cancellation.
- ▲Has Multipoint.
- ▲Has LDAC.
- ▲Battery life: 50 h vs 0 h.
Spec comparison
Design
| Spec | Sennheiser - HD 660S2 | Sony - ULT Wear 2 |
|---|---|---|
| Type | over-ear | over-ear |
| Weight | 260 g | 255 glead |
| Water resistance | none | none |
Audio
| Spec | Sennheiser - HD 660S2 | Sony - ULT Wear 2 |
|---|---|---|
| Driver sizeⓘ | 38 mm | 40 mmlead |
| Impedanceⓘ | 300 Ωlead | 32 Ω |
| Sensitivityⓘ | 104 dBlead | 100 dB |
| Active noise cancellationⓘ | false | truelead |
| Transparency mode | false | truelead |
| Spatial audioⓘ | false | false |
Battery
| Spec | Sennheiser - HD 660S2 | Sony - ULT Wear 2 |
|---|---|---|
| Battery life | 0 h | 50 hlead |
| Fast chargeⓘ | false | truelead |
Connectivity
| Spec | Sennheiser - HD 660S2 | Sony - ULT Wear 2 |
|---|---|---|
| Bluetoothⓘ | 0.0 | 5.3lead |
| Multipointⓘ | false | truelead |
| 3.5mm jack | true | true |
| LDACⓘ | false | truelead |
| aptX HDⓘ | false | false |
Frequently asked
Which has better battery life, HD 660S2 or ULT Wear 2?+
ULT Wear 2 lasts 50 hours vs 0 hours.
Do HD 660S2 or ULT Wear 2 have active noise cancellation?+
ULT Wear 2 has ANC; HD 660S2 does not.
Which supports LDAC, HD 660S2 or ULT Wear 2?+
ULT Wear 2 supports LDAC; HD 660S2 does not.
Spec-level deep dives
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