Bose - QuietComfort Ultra Headphones vs Sennheiser - HD 660S2
Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Bose - QuietComfort Ultra Headphones | Sennheiser - HD 660S2 |
|---|---|---|
| Driver size | 35 mm | 42 mm |
| Weight | 253 g | 260 g |
| Active noise cancellation | true | false |
| Spatial audio | true | false |
| Multipoint | true | false |
| Battery life | 24 h | 0 h |
Between the QuietComfort Ultra Headphones and HD 660S2, the QuietComfort Ultra Headphones comes out ahead in weight / active noise cancellation, while the HD 660S2 wins on driver size. Overall, the QuietComfort Ultra Headphones scores 69.9 and the HD 660S2 scores 52.5 on our Mars Score.
Which should you buy?
The QuietComfort Ultra Headphones is the clear pick on raw spec strength, leading by 17.4 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.
Pick the QuietComfort Ultra Headphones if you carry the device everywhere and weight or thickness has been the deciding factor before. The biggest gaps in its favor are weight, active noise cancellation, spatial audio, among others. The single most decisive one: Weight — 7.00 g less. 253 vs 260.
Pick the HD 660S2 if you care most about driver size. Its strongest claims are driver size. The single most decisive one: Driver size — 20.00% more. 42 mm vs 35 mm.
Both ship with comparable ldac, water resistance, so those specs do not separate the two — focus on the differences below.
Bottom line: the QuietComfort Ultra Headphones is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Which should you buy: Bose - QuietComfort Ultra Headphones or Sennheiser - HD 660S2?
Bose - QuietComfort Ultra Headphones leads the current Mars Score by 17.4 points.The more useful decision is the trade-off behind that result: compare driver size, battery life, weight against the way you will actually use the product.
Choose Bose - QuietComfort Ultra Headphones if…
Bose - QuietComfort Ultra Headphones has the measurable edge on weight g, has anc, has spatial audio.
Choose Sennheiser - HD 660S2 if…
Sennheiser - HD 660S2 has the measurable edge on driver size mm.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Bose - QuietComfort Ultra Headphones wins
- ▲Weight — 7.00 g less. 253 vs 260.
- ▲Has Active noise cancellation.
- ▲Has Spatial audio.
- ▲Has Multipoint.
- ▲Battery life: 24 h vs 0 h.
Why Sennheiser - HD 660S2 wins
- ▲Driver size — 20.00% more. 42 mm vs 35 mm.
Spec comparison
Design
| Spec | Bose - QuietComfort Ultra Headphones | Sennheiser - HD 660S2 |
|---|---|---|
| Type | over-ear | over-ear |
| Weight | 253 glead | 260 g |
| Water resistance | none | none |
Audio
| Spec | Bose - QuietComfort Ultra Headphones | Sennheiser - HD 660S2 |
|---|---|---|
| Driver sizeⓘ | 35 mm | 42 mmlead |
| Impedanceⓘ | 32 Ω | 300 Ωlead |
| Sensitivityⓘ | 100 dB | 104 dBlead |
| Active noise cancellationⓘ | truelead | false |
| Transparency mode | truelead | false |
| Spatial audioⓘ | truelead | false |
Battery
| Spec | Bose - QuietComfort Ultra Headphones | Sennheiser - HD 660S2 |
|---|---|---|
| Battery lifeⓘ | 24 hlead | 0 h |
| Fast chargeⓘ | truelead | false |
Connectivity
| Spec | Bose - QuietComfort Ultra Headphones | Sennheiser - HD 660S2 |
|---|---|---|
| Bluetoothⓘ | 5.3lead | 0 |
| Multipointⓘ | truelead | false |
| 3.5mm jack | true | true |
| LDACⓘ | false | false |
| aptX HDⓘ | truelead | false |
Frequently asked
Which has better battery life, QuietComfort Ultra Headphones or HD 660S2?+
QuietComfort Ultra Headphones lasts 24 hours vs 0 hours.
Do QuietComfort Ultra Headphones or HD 660S2 have active noise cancellation?+
QuietComfort Ultra Headphones has active noise cancellation; HD 660S2 does not.
Which supports LDAC, QuietComfort Ultra Headphones or HD 660S2?+
Neither supports LDAC.