Bose QuietComfort Ultra Headphones (2nd Gen) vs Sennheiser HD 660S2
The Verdict
The Bose QuietComfort Ultra Headphones (2nd Gen) and Sennheiser HD 660S2 sit in the same category and end up appealing to slightly different buyers. The Bose QuietComfort Ultra Headphones (2nd Gen) is the cheaper of the two at $449 versus $499, a difference of about $50. The Bose QuietComfort Ultra Headphones (2nd Gen) is the newer release, which usually means a faster chipset and longer software support. Bose QuietComfort Ultra Headphones (2nd Gen) stands out for 30 hours battery with anc, 45 hours without, while Sennheiser HD 660S2 is praised for reference-grade sound with improved bass over the original hd 660s. Use the side-by-side spec table below to compare cameras, displays, battery life and connectivity in detail and decide which one fits your priorities.
Who Should Buy
Buy the Bose QuietComfort Ultra Headphones (2nd Gen) if…
- →30 hours battery with ANC, 45 hours without
- →USB-C lossless digital audio support
- →Improved adaptive ANC algorithm
Buy the Sennheiser HD 660S2 if…
- →Reference-grade sound with improved bass over the original HD 660S
- →Both 6.35mm and 4.4mm balanced cables included in the box
- →Open-back design creates a wide, natural soundstage
Pros & Cons
Bose QuietComfort Ultra Headphones (2nd Gen)
Pros
- 30 hours battery with ANC, 45 hours without
- USB-C lossless digital audio support
- Improved adaptive ANC algorithm
- Multipoint Bluetooth 5.4 connectivity
- New Cinema Mode for spatial video audio
Cons
- Price increased to $449
- 250g is heavier than some competitors
- No aptX Lossless codec support
Sennheiser HD 660S2
Pros
- Reference-grade sound with improved bass over the original HD 660S
- Both 6.35mm and 4.4mm balanced cables included in the box
- Open-back design creates a wide, natural soundstage
- Lightweight at 260 g for an audiophile over-ear
- Replaceable parts make it a long-term investment
Cons
- 300-ohm impedance requires a dedicated amp/DAC to drive properly
- Wired only — no Bluetooth option
- Open-back leaks significant sound — not for shared spaces
- $499 is steep for headphones that need additional equipment
Full Specifications
| Spec | Bose QuietComfort Ultra Headphones (2nd Gen) | Sennheiser HD 660S2 |
|---|---|---|
| Active Noise Cancelling | ||
| Type | over-ear | over-ear |
| Weight | 250 g | 260 g |
| Battery | ||
| Battery life | 30 hours (ANC on), 45 hours (ANC off) | N/A (wired) |
| Charging | USB-C | N/A |
| Features | Immersive Audio (spatial audio), Cinema Mode for video, USB-C lossless digital audio, Adaptive ANC algorithm, Google Fast Pair, Spotify Tap | Open-back audiophile design, 300-ohm impedance for dedicated amp/DAC use, Balanced 4.4mm Pentaconn cable included, Replaceable ear pads and cables, Handmade in Germany |
| Connectivity | ||
| Wired option | ||
| Codecs | SBC, AAC, aptX Adaptive | |
| Bluetooth | 5.4 | None (wired only) |
| Multipoint | ||
| Drivers | — | 42mm dynamic transducer, 300 ohm impedance |
| Water Resistance | — | None |
Want to compare a third product?
Add another product for a 3-way comparison.
Related Comparisons
- Sennheiser HD 660S2 vs Sony WH-1000XM6
- Bose QuietComfort Ultra Headphones (2nd Gen) vs Sony WH-1000XM6
- Bose QuietComfort Ultra Headphones (2nd Gen) vs Bose QuietComfort Headphones
- Bose QuietComfort Ultra Headphones (2nd Gen) vs Bose QuietComfort 35 II
- Bose QuietComfort Ultra Headphones (2nd Gen) vs Sony WH-1000XM4
- Bose QuietComfort Ultra Headphones (2nd Gen) vs Samsung Galaxy Buds3 Pro
This comparison is based on verified manufacturer specifications covering display, performance, camera, battery, and build quality. Scores are generated by analyzing specs across weighted categories on a 10-point scale. Learn more about our methodology.
Explore more in headphones, see all Bose products or all Sennheiser products. View full details for the Bose QuietComfort Ultra Headphones (2nd Gen) or the Sennheiser HD 660S2.