Sennheiser HD 660S2 Headphones

Dive Deeper Into Legendary Sennheiser Sound

The Sennheiser HD 660S2 combines an intimate, relaxed sound signature with outstanding precision, exceptional comfort, and — new for this generation — genuinely extended sub bass reaching deeper than any prior 600 series model.

Remarkable resolution and precision bring instruments and vocalists closer than ever, yet the sound stays natural and balanced, never harsh or brash even during the most demanding, complex musical passages you can find.

headfonia.com awarded the HD 660S2 its own genuine "Recommended" award, writing simply: "In very short we can say the HD 660S2 is a great headphone with an excellent price/quality ratio."

Where the Revised Coil Earns Its Keep

Double the Sub Bass, Same Precision

The revised coil now matches the 300-ohm impedance of the legendary HD 600 and HD 650, providing higher magnetic force and electrical dampening for genuinely cleaner impulse response throughout every single recording.

Sennheiser doubled sound pressure at the very lowest frequencies while retaining extraordinary precision and balance throughout the sub bass, mid-bass, and beyond — extension that makes highs feel more brilliant against a deeper backdrop.

A More Compliant Surround, Better Airflow

The surround is now more compliant, dropping the resonant frequency to 70Hz, while considerable effort went into optimizing airflow around the transducer for genuinely more efficient overall magnetic gap performance.

Taken together, these measures result in even greater precision, speed, and resolution, with double the sound pressure at the lowest frequencies compared to the outgoing HD 660S it now directly replaces.

Who Is the HD 660S2 Best For?

• You want extended sub bass without losing 600 series precision: the doubled sound pressure at the lowest frequencies is a genuine first for this family
• You want an intimate, relaxed sound over analytical brightness: reviewers consistently describe this tuning as warm and non-fatiguing
• You do super-long listening sessions: the velour earpads and ergonomic headband are built specifically for extended comfort
• You already own an HD 660S and want a genuine upgrade: the revised coil and surround are real engineering advances, not a cosmetic refresh
• You want Sennheiser's open-back reference with deeper bass — the HD 660S2

How Does It Connect to Your System?

A detachable cable connects to each earcup, giving you flexibility to swap or upgrade as your amplifier setup changes, with a standard termination that fits most headphone amplifiers directly.

At 300 ohms, the HD 660S2 genuinely rewards a dedicated headphone amplifier, revealing considerably more of the extended bass and resolution this revised coil is genuinely capable of delivering.

Pairs Well With

What finishes the system around an HD 660S2:

• Headphone amplifiers — genuinely essential at 300 ohms to hear the extended bass this driver delivers
• Digital-to-analog converters — a clean digital source feeding your amp matters as much as the amp itself
• Headphone cables — the detachable design opens the door to balanced or aftermarket options
• Headphone stands — a proper resting spot for a genuine reference instrument

Frequently Asked Questions

Do I need a headphone amplifier for the HD 660S2?

Yes, effectively. At 300 ohms, a phone or laptop won't drive it properly. A dedicated headphone amplifier is genuinely necessary to hear this driver at its best.

How is this different from the original HD 660S?

The revised coil now matches the HD 600/650's 300-ohm impedance and doubles sound pressure at the lowest frequencies, a genuine engineering advance rather than a cosmetic refresh.

How does this compare to the HD 650?

Both share the 300-ohm platform and a warm, intimate signature, but the HD 660S2 adds genuinely extended sub bass the HD 650 was never designed to reach.

Can I use these away from home?

Not really. The HD 660S2 is open-back and leaks sound significantly in both directions, so it's built for a quiet room rather than shared or mobile spaces.

Are these comfortable for long sessions?

Yes. The velour earpads and low total weight practically beg you to keep going, and the ergonomic headband rules out discomfort on top of your head.

Where is the HD 660S2 made?

Manufactured in Ireland, the same facility responsible for Sennheiser's entire high-end reference headphone lineup, ensuring consistent quality across every single unit built.

See It in Action

Sennheiser presents All About Our HD 660S2 with @Tyler.fortherecord | Sennheiser.

SoundStage! Network presents Sennheiser HD 660S2 Headphones Review. Are They Worth the Price?.

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