Sennheiser HD 660S2 Review: Classic Dynamics, Modern Bass

Headphone Product Library · 完整规格

声学规格 · 数据一览

In 2023, Sennheiser launched the HD 660S2 building upon the HD 660S. This headphone is not a simple iteration but a direct response to the controversial feedback regarding the low-frequency response of the older model. As the latest member of the HD 600 series, it continues the series' classic status among audiophiles while attempting to incorporate low-frequency expressiveness that aligns with modern listening preferences, all while preserving the traditional dynamic driver character. Its 38mm dynamic driver and 300-ohm impedance clearly target desktop Hi-Fi scenarios that require a dedicated headphone amplifier, rather than serving as a compromise for direct connection to portable devices.

In terms of comfort, the HD 660S2 continues Sennheiser's iconic family design language: a dark grey plastic housing, open-back metal mesh grilles, and generously padded velour earcups. The overall build feels solid and highly recognizable. At 260 grams, it sits at a moderate weight among open-back over-ear headphones. Combined with a well-distributed clamping force, pressure distribution remains reasonable during extended listening sessions, and the headband padding is sufficiently soft. However, the internal space of the earcups is not particularly spacious, and users with larger ears may experience slight pressure. Overall, it is a securely fitting headphone suitable for long listening sessions, though it does not make extra strides in weight reduction or material innovation.

Sonically, the most notable change in the HD 660S2 lies in its enhanced low-frequency energy, which gives it a warmer, fuller modern tuning compared to its predecessor. It does not sacrifice the natural smoothness characteristic of dynamic drivers; the overall sound retains a relaxed, unstrained quality, yet the thickness and impact of the low end are noticeably increased, grounding the music's center of gravity lower. This tuning approach allows it to deliver richer rhythmic drive and atmosphere when reproducing pop, electronic, and other contemporary music genres, moving away from the traditional impression of the Sennheiser HD 6 series as being more mid-high focused, slightly reserved, and classical-leaning.

Looking at specific frequency bands, the bass is the core of this upgrade. Bass quantity is generous, with noticeably improved extension compared to the older model. Drum hits exhibit firmer impact and elasticity, yet there is no excessive or overwhelming boom; control remains excellent. In the midrange, vocals retain Sennheiser's signature thickness and density, with clear articulation and well-positioned imaging, delivering a warm and emotive texture that shines particularly with male vocals and jazz. The treble presents smooth, gentle extension with moderate brightness, without overemphasizing detail retrieval or airiness, avoiding harsh or piercing qualities. This makes long listening sessions fatigue-free, though it may come across as slightly reserved for listeners seeking ultimate detail.

Based on its sonic character, the HD 660S2 is ideally suited for pop vocals, jazz, rock, and electronic music—genres that emphasize rhythm and atmosphere. For smaller-scale classical works, it also delivers excellent musicality thanks to its outstanding midrange texture. However, in large-scale symphonic pieces, its soundstage is relatively limited, and layering is not as expansive as flagship models. It is best suited for users with dedicated headphone amplifiers and desktop DACs in their systems, especially seasoned audiophiles who prefer a warm, full-bodied tone while wanting to retain the natural sound of dynamic drivers. For beginners or those driving headphones directly from smartphones, the 300-ohm impedance may prevent the headphone from reaching its full potential.

In summary, the HD 660S2 represents a successful "modern" refinement. Without compromising the classic midrange character of the HD 6 series, it addresses the low-frequency shortcoming, making it a more versatile dynamic headphone better adapted to modern music tastes. While it may not be the strongest in its price range in terms of ultimate resolution and soundstage scale, its balanced, fatigue-free tuning and solid build make it a reference-grade choice worth considering. As for purchasing advice: if you already own a good headphone amplifier system and prefer a warm, full-bodied, and musical sound, this headphone is worth acquiring. However, if you prioritize ultimate transparency and soundstage, or primarily rely on portable devices for driving, it is advisable to audition it first or consider other models better suited for direct connection.