Sennheiser HD 660S2 Open-Back Audiophile Headphones

Overview

The Sennheiser HD 660S2 High-Definition Open-Back Headphones are premium audiophile headphones engineered for exceptional detail, natural sound reproduction, and extended low-frequency performance. Designed for discerning music enthusiasts, audio professionals, and critical listeners, the HD 660S2 builds upon the acclaimed HD 600 series with deeper sub-bass extension, enhanced dynamics, and outstanding precision while maintaining the signature warm and natural Sennheiser sound.

Featuring precision-engineered 38 mm dynamic drivers, an open-back design, and a lightweight yet durable construction, the HD 660S2 delivers an expansive soundstage, lifelike imaging, and long-lasting comfort for extended listening sessions. Designed in Germany and manufactured in Ireland, these headphones are ideal for high-fidelity home audio systems, dedicated headphone amplifiers, and professional studio monitoring.

Key Features

• Premium open-back audiophile headphones
• 38 mm dynamic transducers with improved low-frequency performance
• Extended sub-bass response down to 8 Hz
• Natural, warm, and highly detailed sound signature
• 300-ohm impedance optimized for high-end audio equipment
• Ultra-light aluminum voice coil for excellent transient response
• Vented magnet system minimizes distortion
• Comfortable velour ear cushions for extended listening
• Replaceable dual-sided detachable cables
• Designed in Germany and made in Ireland

Exceptional Audiophile Sound

The HD 660S2 delivers remarkable clarity, tonal balance, and imaging with an extended low-end response that enhances bass depth without sacrificing midrange accuracy. Its open-back acoustic design creates a spacious and natural listening experience ideal for classical, jazz, acoustic, rock, and high-resolution music playback.

Designed for Critical Listening

With its 300-ohm impedance and precision-engineered drivers, the HD 660S2 pairs exceptionally well with dedicated headphone amplifiers and premium audio interfaces. The result is highly accurate sound reproduction suitable for mastering, mixing reference, and immersive music enjoyment.

Comfort for Long Listening Sessions

Soft velour ear cushions, an ergonomic headband, and lightweight construction provide exceptional comfort during extended listening. The open-back architecture also promotes airflow, helping reduce listening fatigue over long sessions.

Specifications

• Model: HD 660S2
• Product Type: Open-Back Over-Ear Headphones
• Transducer Principle: Dynamic
• Driver Size: 38 mm
• Frequency Response: 8 Hz – 41,500 Hz
• Impedance: 300 Ω
• Sound Pressure Level (SPL): 104 dB (1 kHz, 1 Vrms)
• Total Harmonic Distortion (THD): <0.04% (1 kHz, 100 dB SPL)
• Ear Coupling: Over-Ear
• Weight: Approx. 260 g
• Cable Length: 1.8 m
• Country of Manufacture: Ireland

What's Included

• Sennheiser HD 660S2 Open-Back Headphones
• 1.8 m Cable with 6.35 mm Stereo Plug
• 1.8 m Balanced Cable with 4.4 mm Plug
• 6.35 mm to 3.5 mm Adapter
• Protective Carrying Pouch
• User Documentation

Why Choose the Sennheiser HD 660S2?

The Sennheiser HD 660S2 is an outstanding choice for audiophiles, music producers, and critical listeners seeking reference-quality sound with enhanced bass extension, exceptional detail retrieval, and all-day comfort. Combining premium craftsmanship, precision engineering, and the legendary HD 600-series sound signature, it delivers an immersive listening experience for high-resolution music, professional monitoring, and home hi-fi systems.