Sennheiser HD 660S2 Hands-On Review: Real-World Sound, Isolation & Comfort
Sub-bass extension and warm vocal intimacy for dedicated listening rigs.
Calculated across 5 balanced evaluation pillars
5-Pillar Evaluation Breakdown
✓Key Advantages
- •Legendary midrange vocal rendering
- •Deeper sub-bass response than predecessor HD 650
- •Velour ear cushions never overheat
✕Noted Trade-offs
- •Requires dedicated headphone DAC/Amp (300Ω)
- •Open grille leaks audio into quiet rooms
Hardware Specifications
- Driver
- 38mm Open Transducer (300 Ohm)
- Battery Life
- Wired (No Battery)
- Weight
- 260g
- Bluetooth
- None (6.3mm / 4.4mm Balanced)
- Fast Charging
- N/A (Analog Wired)
How We Test & Evaluate
At SoundGearHQ, our evaluation of the Sennheiser HD 660S2 was conducted across real living rooms, daily transit commutes, and dedicated desktop listening stations over a multi-week assessment period.
We focus on practical listening comfort—measuring headband clamping pressure during extended 3-hour sessions, Bluetooth signal stability through walls and busy streets, microphone clarity during voice calls in coffee shops, and battery endurance matched against manufacturer claims.
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