Bose QuietComfort 35 II vs Sennheiser HD 660S2
The Verdict
Bose QuietComfort 35 II and Sennheiser HD 660S2 serve distinctly different audiophile needs. Bose prioritizes active noise cancellation with three levels, wireless convenience via Bluetooth 4.2, and 20-hour battery life, making it ideal for travelers and commuters. Google Assistant integration and a foldable design add practical appeal. Sennheiser HD 660S2 takes the opposite approach as a wired, open-back audiophile headphone with 42mm dynamic drivers and 300-ohm impedance, demanding a dedicated amplifier setup for optimal sound. Handmade German construction ensures premium build quality. Sound signature differs dramatically: Bose emphasizes balanced, portable listening with ANC refinement; Sennheiser delivers detailed, spacious soundstage for studio monitoring and critical listening. Budget-conscious travelers should choose Bose, while audiophiles with amplification equipment prefer Sennheiser. Price reflects purpose: Bose at $299 offers exceptional wireless value, while Sennheiser's $499 investment targets serious listeners prioritizing audio fidelity over convenience.
Who Should Buy
Buy the Bose QuietComfort 35 II if…
- →Legendary Bose noise cancellation that set the industry standard
- →Extremely comfortable for all-day wear with plush ear cushions
- →20-hour battery life is solid for travel and commuting
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
Category Scores
Pros & Cons
Bose QuietComfort 35 II
Pros
- Legendary Bose noise cancellation that set the industry standard
- Extremely comfortable for all-day wear with plush ear cushions
- 20-hour battery life is solid for travel and commuting
- Dedicated Google Assistant button for quick voice commands
- Foldable design and included hard case for portability
Cons
- Bluetooth 4.2 lacks modern codecs like aptX and LDAC
- Micro-USB charging port is outdated — not USB-C
- Sound quality is beaten by newer XM4 and XM5 models
- No multipoint Bluetooth for connecting two devices simultaneously
- Plastic build shows wear over time
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 35 II | Sennheiser HD 660S2 |
|---|---|---|
| Active Noise Cancelling | ||
| Type | over-ear | over-ear |
| Weight | 235 g | 260 g |
| Battery | ||
| Battery life | 20 hrs (wireless with ANC), 40 hrs (wired with ANC) | N/A (wired) |
| Charging | Micro-USB, 2.25 hrs for full charge, 15 min = 2.5 hrs playback | N/A |
| Drivers | 40mm Bose custom drivers | 42mm dynamic transducer, 300 ohm impedance |
| Features | Three levels of ANC (High, Low, Off), Google Assistant built-in (dedicated button), Bose AR (augmented reality) compatible, Volume-optimized EQ, Foldable design with carry case | 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 | AAC, SBC | |
| Bluetooth | 4.2 with NFC pairing | None (wired only) |
| Multipoint | ||
| Water Resistance | None | None |
Related Comparisons
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 35 II or the Sennheiser HD 660S2.