Sennheiser Consumer Audio HD 660S2 Wired Audiophile Stereo Headphones Review

For decades, Sennheiser’s HD 600 series has been the gold standard for audiophile open-back headphones. From the HD 600’s natural reference tuning to the HD 650’s warmth and the HD 660S’s modern refinements, each iteration has carried a legacy of precision, comfort, and long-term value.

Now, with the Sennheiser HD 660S2, Sennheiser has taken its iconic formula and refined it even further—offering deeper sub-bass extension, optimized airflow for smoother response, and improved driver design with a vented magnet system and aluminum voice coil. The result is a headphone that maintains the HD series’ legendary balance while adding richness, punch, and immersion.

Sale

Sennheiser Consumer Audio HD 660S2 – Wired Audiophile Stereo…

Natural, relaxed, high-fidelity sound with extra sub bass: Ultra-light aluminum voice coil with 300-ohm impedance for excellent impulse response and an intimate sound with great timbre

Premium Build & Design

The HD 660S2 follows Sennheiser’s tradition of minimalist, functional, and durable construction.

Matte Black Finish: Elegant, understated design with a professional aesthetic.
Open-Back Ear Cups: Large, oval-shaped grills allow airflow for spacious sound.
Replaceable Parts: Pads, headband cushions, and cables can all be swapped, extending lifespan.
Cables: Includes balanced and unbalanced detachable cables for flexibility with amps/DACs.
Headband Frame: Reinforced yet lightweight, designed for daily use over years.

While simple, the design reflects Sennheiser’s engineering-first philosophy: everything is built for comfort, longevity, and performance.

Comfort & Ergonomics

The HD 660S2 is designed for hours of uninterrupted listening.

Weight: ~260g, making it significantly lighter than many competing audiophile headphones.
Clamping Pressure: Firm at first but loosens slightly after break-in, giving a secure yet comfortable fit.
Velour Earpads: Soft, breathable, and ideal for long sessions without heat buildup.
Headband: Well-cushioned, distributes weight evenly across the crown.

Whether you’re a music listener, gamer, or studio professional, this headset is comfortable enough for marathon sessions.

Sound Signature – The HD 660S2 Experience

The hallmark of the HD 600 series has always been balanced, natural sound, and the HD 660S2 builds on that with more authority in the low end.

Bass

Deeper sub-bass extension than previous models, thanks to optimized airflow and vented magnet system.
Adds rumble and presence in genres like EDM, hip-hop, or cinematic scores without becoming bloated.
Bass remains tight and articulate, preserving detail in acoustic and jazz recordings.

Mids

Natural and forward mids—the soul of the HD 600 lineage.
Vocals, acoustic instruments, and dialogue sound intimate and lifelike.
Ideal for critical listening and studio monitoring.

Treble

Smooth and slightly rolled off compared to brighter headphones, reducing fatigue.
Detailed enough for classical and orchestral music, but never harsh.
Perfect balance between clarity and comfort.

Soundstage & Imaging

Open-back design provides a wide, airy stage with precise imaging.
Not artificially wide—more natural, like sitting in a well-treated room.
Instrument separation is excellent, making it great for critical listening, mixing, and even competitive gaming.

Technical Refinements Over the HD 660S

The S2 isn’t just a cosmetic refresh—it’s a true upgrade:

New Voice Coil: Aluminum coil for better efficiency and transient response.
Improved Sub-Bass: Now reaches lower frequencies with impact, giving a more full-range sound.
Optimized Airflow System: Reduces distortion and smooths frequency response.
Impedance: 300 ohms, consistent with the HD 600 lineage—best paired with a dedicated DAC/amp.
Balanced Connectivity: Ships with both balanced (4.4mm Pentaconn) and unbalanced (6.3mm) cables for flexible setups.

The result? A headphone that feels more versatile than the HD 660S, equally at home with orchestral scores and bass-heavy electronic music.

Use Cases

The HD 660S2 is incredibly versatile:

Audiophile Listening: Perfect for genres like classical, jazz, folk, and acoustic. The added bass also makes it enjoyable for EDM and hip-hop.
Studio Mixing & Mastering: Accurate mids and imaging make it reliable for professionals.
Gaming: While not marketed as a “gaming headset,” its wide stage and precise imaging make it superb for immersive single-player and competitive FPS. Pair it with a ModMic for comms.
Movies & Streaming: Open, natural presentation makes films feel cinematic without artificial processing.

Check Limited Exclusive Price Today

Pros & Cons

Pros
✔ Legendary HD 600-series DNA
✔ Deeper sub-bass extension for a fuller sound
✔ Excellent mids and natural tonality
✔ Lightweight & extremely comfortable
✔ Serviceable design with replaceable parts
✔ Includes balanced & unbalanced cables

Cons
❌ Requires proper amplification (not ideal for smartphones)
❌ Open-back leaks sound—unsuitable for noisy/shared environments
❌ Treble may feel too smooth for fans of bright headphones
❌ Premium pricing compared to HD 650/660S

FAQs

Q: Do I need an amp for the HD 660S2?
Yes—at 300 ohms, it performs best with a quality DAC/amp. It will sound underpowered directly from a phone or laptop.

Q: How does it compare to the HD 660S?
The HD 660S2 offers deeper bass extension, smoother overall response, and more efficiency, making it more versatile for modern music.

Q: Is it good for gaming?
Yes—its imaging and soundstage make it excellent for competitive shooters and immersive RPGs, though you’ll need an external mic.

Q: How does it compare to the HD 650?
The HD 650 is warmer, the HD 660S2 is more dynamic with stronger bass and slightly cleaner treble.

Final Verdict

The Sennheiser HD 660S2 is a worthy successor to the legendary HD 600 family. By adding deeper bass extension and technical refinements while keeping the natural mids and smooth treble that made the series famous, Sennheiser has created one of the most versatile open-back headphones available in 2025.

If you’re an audiophile, critical listener, or gamer who values accuracy and immersion, the HD 660S2 is an outstanding investment. It’s not for bass-junkies or casual mobile use, but with the right DAC/amp, it delivers world-class sound that grows with your setup.

👉 [Check Latest Price on Amazon]

Latest Post: JBL quantum 910x wireless over ear hi-res certified quantumsound gaming headset

Post Views: 5