If you're an audiophile searching for the perfect pair of headphones, look no further than the Sennheiser Consumer Audio HD 660S2. Renowned for its high-fidelity sound and exceptional build quality, this model promises an immersive listening experience.

Priced at $499.00 and boasting a 4.5 out of 5 rating from 302 reviews, the HD 660S2 is designed for serious music lovers. Let's dive into what makes these headphones a must-have for any sound enthusiast.

I got these headphones during a Black Friday sale for $400, and they have quickly become my favorite. The sound quality is unmatched, offering a balanced, warm sound with excellent sub-bass performance. They excel in instrument separation and provide a wide soundstage, making them perfect for any genre of music.

Comfort is another area where the HD 660S2 shines. The plush ear cushions and open-back design make them extremely comfortable for long listening sessions. However, it's essential to pair these with a good DAC and amp to truly appreciate their capabilities.

Sound Quality

Hi Fi headphones

The Sennheiser Consumer Audio HD 660S2 headphones are notable for their natural, relaxed, high-fidelity sound with an emphasis on deep sub-bass. The inclusion of an ultra-light aluminum voice coil with a 300-ohm impedance ensures excellent impulse response and an intimate sound with great timbre. Users have praised the headphones for their wide soundstage, excellent instrument separation, and balanced, warm sound profile. The mids and treble are particularly well-executed, with the treble being sparkly and nimble without causing fatigue.

Comfort and Build Quality

High End headphones

These headphones are designed with user comfort in mind. The open-back design offers exceptional breathability, while the plush ear cushions deliver maximum comfort, making them suitable for long listening sessions. Users with larger heads have reported that the headphones do not clamp too tightly, providing a good acoustic seal without causing discomfort. The build quality is exceptional, designed in Germany and made in Ireland, ensuring durability and longevity.

Driving Equipment

High-end headphones

To achieve the best performance from the HD 660S2, a headphone amplifier or a properly specified piece of equipment is recommended. Without an amplifier, the headphones may sound soulless or muddy. However, they scale well with good sound equipment, such as an entry-level Schiit DAC+Amp stack, which can significantly enhance their sound quality. Potential buyers should consider the additional cost of an amplifier and DAC unit, which can add at least $200 to the overall expense.

Bass Performance

High-End Headphones

The HD 660S2 headphones excel in delivering double the sound pressure at the lowest octaves. Users can feel the lowest notes on a piano or the kick of a bass drum as if they were present in the recording studio. The bass is described as nimble and detailed, with kick drums punching hard and low frequencies playing at good volume. Some users may prefer to boost the low shelf EQ filter centered at 40Hz for even more bass, but the stock tonality is generally considered excellent.

Use Case and Versatility

HIFI Headphones

These headphones are primarily designed for sitting at a personal desk and listening to music. They are not ideal for traveling, office use, or gaming. The target audience is relatively niche, focusing on users who prioritize high-fidelity sound for music listening. This specific use case has led to mixed reviews on various headphone rating sites, but those who fit the target audience find the HD 660S2 to be exceptionally satisfying.

Frequency Response

HIFI headphones

With a frequency response of 8 Hz to 41,500 Hz, the HD 660S2 headphones offer an extensive range that allows users to hear more details and detect varying characteristics of musical instruments and vocal styles. The sound imaging is refined, providing a textured musical experience that makes music feel life-like. Users have noted that the extended range contributes to a more immersive listening experience.

Soundstage and Imaging

HIFI headphones

The HD 660S2 headphones provide a soundstage with depth and height, though it may not be as wide as some other models. However, the imaging is outstanding, with every voice and instrument well-defined and occupying a reliable spot in the 3D soundstage. This makes the headphones suitable for both music and gaming, as the precise imaging enhances the overall experience.

Aesthetic and Design

The headphones are visually appealing, with a sleek black design that reflects their premium quality. The build quality and fit are excellent, and they look great when worn. The open-back design not only contributes to their sound quality but also adds to their aesthetic appeal. Users have praised the headphones for their comfortable fit and stylish appearance.

Price and Value

While the HD 660S2 headphones are priced at $499, some users believe they are a bit overpriced at MSRP. However, when available on sale at around $400, they are considered a good value for the sound quality and comfort they offer. The headphones provide a beautiful and emotional musical experience, making them worth the investment for audiophiles.

User Feedback and Reviews

Overall, the HD 660S2 headphones have received positive reviews, with a rating of 4.5 out of 5 stars based on 302 reviews. Users have highlighted their excellent sound quality, comfort, and build quality. However, some have noted that these headphones require a good amplifier and DAC to reach their full potential. Despite this, the majority of users find them to be an outstanding choice for high-fidelity music listening.


  • Excellent sub-bass performance
  • Exceptional comfort for long listening sessions
  • High-fidelity sound with great timbre


  • Requires a dedicated amp/DAC for best performance
  • Pricey at MSRP
  • Limited soundstage compared to competitors


In summary, the Sennheiser HD 660S2 headphones are an excellent investment for audiophiles seeking top-notch sound quality and comfort. While they may seem pricey, especially with the need for additional equipment, the superior audio experience they offer is well worth it.

If you're willing to invest in quality sound equipment, the HD 660S2 will not disappoint. These headphones provide a beautiful and emotional musical experience, making them a standout choice in the audiophile market.

Questions & Answers:

Question: Do these headphones require a dedicated amp?

Answer: Yes, to achieve the best sound quality, it is recommended to use these headphones with a dedicated amp/DAC.

Question: Are these headphones comfortable for long listening sessions?

Answer: Yes, the HD 660S2 offers exceptional comfort with its plush ear cushions and open-back design, making them suitable for long listening sessions.

Question: How does the bass performance compare to other models?

Answer: The HD 660S2 has superior sub-bass performance compared to other models in the Sennheiser 600 series, providing a more immersive listening experience.