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Sennheiser HD 660S — Open-back
Sennheiser

Sennheiser HD 660S

Open-back

90
/ 100
From $499
VS
Bose QuietComfort Ultra 2 wins by 3
Bose QuietComfort Ultra 2 — World-class ANC · 30hr · Immersive Audio
Bose

Bose QuietComfort Ultra 2

World-class ANC · 30hr · Immersive Audio

93
/ 100
From $449
Specdex verdict

Bose QuietComfort Ultra 2 takes it — here’s why.

In our weighted Specdex score, Sennheiser HD 660S lands at 90 and Bose QuietComfort Ultra 2 at 93. That puts Bose QuietComfort Ultra 2 ahead by 3 points — a narrow margin driven mostly by its strengths in the categories below.

Pick Sennheiser HD 660S if…

  • ✓Reference-level detail
  • ✓Well-regarded in audiophile community
  • ✓Long-term ownership appeal

Pick Bose QuietComfort Ultra 2 if…

  • ✓Deepest ANC on the market
  • ✓Comfortable for 8hr+ flights
  • ✓Bose Immersive Audio
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Winner by scenario

Derived from the sub-score breakdown · not a separate test

Sound quality

Tie

Tuning, detail, and staging

Effectively tied — neither pulls a 2-point weighted lead.

Noise cancelling

Bose QuietComfort Ultra 2

ANC strength for commute and travel

Bose QuietComfort Ultra 2 leads on anc (100 vs 0).

Comfort

Bose QuietComfort Ultra 2

Long-session wearability

Bose QuietComfort Ultra 2 leads on comfort (96 vs 88).

Value for money

Bose QuietComfort Ultra 2

Specdex score per dollar at MSRP

Bose QuietComfort Ultra 2 more score per dollar ($449 vs $499).

Sennheiser HD 660S 90
vs
93 Bose QuietComfort Ultra 2

Score breakdown

Sennheiser HD 660S
90
anc 0
sound 90
comfort 88
battery 100
features 50
Bose QuietComfort Ultra 2
93
anc 100
sound 90
comfort 96
battery 88
features 92

Specs side-by-side

Sennheiser HD 660S versus Bose QuietComfort Ultra 2 — full spec comparison
Spec Sennheiser HD 660S Bose QuietComfort Ultra 2
Type
Open-back
—
Driver
—
35 mm
ANC
—
Hybrid · 8-mic
Bluetooth
—
5.3 + Snapdragon Sound
Codecs
—
aptX Adaptive + AAC + SBC
Battery
—
30 hr (24 with ANC)
Charging
—
USB-C, 15-min for 2.5hr
Weight
—
254 g

Sennheiser HD 660S

Pros
  • +Reference-level detail
  • +Well-regarded in audiophile community
  • +Long-term ownership appeal
Cons
  • −Requires amplifier (most)
  • −No active noise cancellation
  • −Impractical for commuting

Bose QuietComfort Ultra 2

Pros
  • +Deepest ANC on the market
  • +Comfortable for 8hr+ flights
  • +Bose Immersive Audio
Cons
  • −No multi-point with 2025 firmware bug
  • −Cable not included
  • −Pricier than XM6

FAQ: Sennheiser HD 660S vs Bose QuietComfort Ultra 2

Which is better, Sennheiser HD 660S or Bose QuietComfort Ultra 2? +

Bose QuietComfort Ultra 2 scores 93 on our weighted rubric — ahead by 3. Your best pick depends on the sub-scores above.

Is Sennheiser HD 660S worth the price? +

At $499, Sennheiser HD 660S delivers a Specdex score of 90 — strongest in battery.

Is Bose QuietComfort Ultra 2 worth the price? +

At $449, Bose QuietComfort Ultra 2 delivers a Specdex score of 93 — strongest in anc.

Does Sennheiser HD 660S or Bose QuietComfort Ultra 2 last longer? +

Based on our long-term update and support ratings, both ship with multi-year support. Battery and reliability scores are visible in the breakdown above.

Which is better for noise cancelling, Sennheiser HD 660S or Bose QuietComfort Ultra 2? +

Bose QuietComfort Ultra 2 — leads on anc (100 vs 0). ANC strength for commute and travel.

Which is better for comfort, Sennheiser HD 660S or Bose QuietComfort Ultra 2? +

Bose QuietComfort Ultra 2 — leads on comfort (96 vs 88). Long-session wearability.