Bose QuietComfort 45 vs Sennheiser HD 660S2
The Verdict
Bose QuietComfort 45 and Sennheiser HD 660S2 serve fundamentally different listeners. Bose delivers active noise cancellation, 24-hour wireless battery life, and Bluetooth 5.1 multipoint connectivity,ideal for commuters and mobile users prioritizing convenience. Sound is balanced and engaging with customizable EQ. Sennheiser HD 660S2 is a wired audiophile headphone featuring 42mm dynamic drivers, 300-ohm impedance, and an open-back design requiring a dedicated amplifier setup. Soundstage and detail retrieval excel for critical listening in controlled environments. Choose Bose if you need ANC, portability, and wireless freedom; choose Sennheiser if you're a serious audiophile willing to invest in proper amplification and don't require wireless capability. They're incomparable in practice despite both being premium over-ears.
Who Should Buy
Buy the Bose QuietComfort 45 if…
- →Legendary Bose ANC is among the best in the industry
- →Incredibly comfortable for all-day wear with plush ear cushions
- →Lightweight at 240 g — easy to forget you're wearing them
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 45
Pros
- Legendary Bose ANC is among the best in the industry
- Incredibly comfortable for all-day wear with plush ear cushions
- Lightweight at 240 g — easy to forget you're wearing them
- 24-hour battery handles long trips without charging
- Reliable Bose sound signature with warm, balanced audio
Cons
- No LDAC or aptX — limited to SBC/AAC codecs
- No water resistance for outdoor or gym use
- Cannot adjust ANC levels — only full ANC or Aware mode
- Aware mode sounds less natural than Sony's ambient mode
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 45 | Sennheiser HD 660S2 |
|---|---|---|
| Active Noise Cancelling | ||
| Type | over-ear | over-ear |
| Weight | 240 g | 260 g |
| Battery | ||
| Battery life | 24 hrs | N/A (wired) |
| Charging | USB-C, 15 min = 3 hrs playback | N/A |
| Drivers | Bose proprietary driver | 42mm dynamic transducer, 300 ohm impedance |
| Features | Active Noise Cancellation, Aware mode (transparency), Bose SimpleSync, Adjustable EQ via Bose Music app, Multipoint connection | 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 | |
| Bluetooth | 5.1 | 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 45 or the Sennheiser HD 660S2.