Sennheiser HD 660S2 Review 2026: Still Worth It?

Are you looking for a premium open-back headphone that delivers warm, detailed sound without breaking the bank?

The Sennheiser HD 660S2 has been a hot topic in the audiophile world since its release in early 2023.

It promises deep sub-bass, a refined midrange, and classic Sennheiser comfort. But does it still hold up in 2026?

In this full review, we break down everything you need to know about the HD 660S2. We cover the sound quality, build, comfort, specs, and value for money.

Key Takeaways

• The Sennheiser HD 660S2 is an open-back, over-ear headphone with a 300-ohm impedance and a frequency response of 8 Hz to 41,500 Hz. It handles everything from deep sub-bass to airy highs.
• Sound quality is warm, intimate, and natural. The HD 660S2 adds noticeable sub-bass compared to its predecessor, the HD 660S, while keeping the beloved midrange clarity Sennheiser is known for.
• Build quality stays true to the classic 600-series design. You get a lightweight plastic frame, velour ear pads, and a sturdy headband. It is comfortable for long listening sessions.
• It needs an amplifier to shine. At 300 ohms, this headphone benefits greatly from a dedicated headphone amp or a quality DAC/amp combo. Plugging it straight into a phone will leave you disappointed.
• Current street price sits around $400 to $450, which is a significant drop from its original $600 MSRP. This makes it a much stronger value proposition in 2026 than it was at launch.
• Strong alternatives exist at similar price points, including the Beyerdynamic DT 900 Pro X, the HiFiMAN Sundara, and the Sennheiser HD 650. Your best pick depends on your sound preference and use case.

Sennheiser HD 660S2 Overview and First Impressions

The Sennheiser HD 660S2 arrived in early 2023 as an update to the popular HD 660S. It belongs to Sennheiser’s legendary 600-series lineup. This series includes the HD 600, HD 650, and HD 660S, all of which are considered benchmarks in the audiophile community.

Your first impression out of the box is familiar. The packaging is clean and minimal. Inside, you get the headphone, a 6.35mm to 3.5mm adapter, and a detachable cable. The cable terminates in dual-sided connectors at the ear cups. It feels solid without being bulky.

On your head, the HD 660S2 feels light and secure. The clamping force is moderate. It holds its position well without causing pressure on your temples or the top of your head. If you have used any Sennheiser 600-series headphone before, this will feel like home.

Design and Build Quality

The HD 660S2 uses the same tried-and-true design language as the rest of the 600-series. The frame is made of reinforced plastic with metal grilles on the ear cups. It looks understated and professional. There are no flashy accents or RGB lights here.

The ear pads are covered in soft velour. They feel plush against your skin and allow airflow, which keeps your ears cool during long sessions. The headband padding is also velour-covered and distributes weight evenly across the top of your head.

Some listeners wish Sennheiser had upgraded the materials for a more premium feel at this price point. The plastic frame can creak slightly if you twist it. Still, the 600-series design has proven itself over decades. These headphones are durable and can handle daily use without issues.

Sound Quality: How Does the HD 660S2 Perform?

Sound quality is the main reason anyone buys the HD 660S2. And it delivers. The tuning is warm, slightly dark, and very natural. Vocals sound rich and present. Instruments have good separation and texture.

The biggest change from the HD 660S is the extended sub-bass. Sennheiser lowered the resonant frequency from 110 Hz to 70 Hz. This means the HD 660S2 reaches deeper into the low end. Kick drums have more weight. Bass guitars have more body. It is a welcome improvement.

Midrange performance remains excellent. This is where Sennheiser headphones have always excelled. The rise from 500 Hz to 2 kHz gives voices a beautiful clarity and warmth. Acoustic tracks, jazz, and vocal-heavy music sound stunning on these cans.

Bass Response: Deep, Clean, and Controlled

The bass on the HD 660S2 is one of its standout features. Previous 600-series models were often criticized for thin or polite bass. The HD 660S2 fixes this problem with deeper extension and a fuller low-end presence.

Sub-bass rumble is audible and enjoyable. It does not overpower the midrange or bleed into other frequencies. The bass stays tight and controlled. You can hear individual bass notes clearly, which is important for genres like jazz, classical, and acoustic music.

However, if you are a bass-head who listens to EDM or hip-hop, the HD 660S2 may still feel restrained. It does not slam or punch the way a closed-back or planar magnetic headphone does. The bass is refined, not aggressive. For most audiophile listeners, this is exactly the right approach.

Top 3 Alternatives for Sennheiser HD 660S2

If the HD 660S2 does not match your exact needs, these three alternatives offer excellent performance at similar price points.

1. Beyerdynamic DT 900 Pro X — A studio-focused open-back headphone with a wider soundstage and brighter tuning. It runs at 48 ohms, so it is much easier to drive from any source. Great for mixing and critical listening.

2. HiFiMAN Sundara — A planar magnetic open-back headphone with lightning-fast transients and excellent detail retrieval. It offers a different flavor of sound compared to Sennheiser’s dynamic driver approach. Bass speed and resolution are exceptional on the Sundara.

3. Sennheiser HD 650 — The classic that started it all. The HD 650 offers a warmer, more laid-back sound compared to the HD 660S2. It has less sub-bass extension but a famously smooth and forgiving midrange. Often available at a lower price.

Midrange and Treble Performance

The midrange is the heart and soul of the HD 660S2. Sennheiser has always tuned the 600-series for vocal clarity and natural timbre. The HD 660S2 continues this tradition. Voices sound lifelike. Guitars have texture and bite. Piano notes ring true without harshness.

The treble is smooth and well-extended. It reaches up to 41,500 Hz on paper. In practice, the highs feel airy and open without any sibilance or sharpness. This makes the HD 660S2 a great choice for listeners who are sensitive to bright treble. You can listen for hours without fatigue.

Some reviewers note that the treble can feel slightly recessed compared to the HD 600 or HD 660S. This is intentional. Sennheiser tuned the HD 660S2 for a warmer, more relaxed presentation. If you prefer sparkle and energy in the highs, you may want to look at the Beyerdynamic DT 900 Pro X instead.

Soundstage and Imaging

Open-back headphones are known for their spacious sound. The HD 660S2 delivers a good soundstage, but it leans toward an intimate presentation. The sound feels close and personal, like sitting in the front rows of a small concert hall.

Imaging is accurate. You can pinpoint instruments in the stereo field with ease. Left-to-right separation is clear and precise. This makes the HD 660S2 a solid pick for critical listening and casual enjoyment alike.

That said, the soundstage is not the widest in its class. Headphones like the Beyerdynamic DT 900 Pro X or the Sennheiser HD 800S offer a noticeably larger sense of space. If you prioritize a wide, airy soundstage above all else, the HD 660S2 may feel a bit narrow for your taste.

Comfort and Fit for Long Listening Sessions

Comfort is a major strength of the HD 660S2. It weighs approximately 260 grams without the cable. That is light enough to wear for hours without neck strain. The velour ear pads are soft, breathable, and gentle on the skin.

The oval ear cup shape fits most ear sizes well. The clamping force is firm enough to keep the headphone in place but not so tight that it causes discomfort. Over time, the clamp loosens slightly for an even better fit.

The headband distributes pressure evenly. There are no hot spots on the top of your head. If you wear glasses, you may feel slight pressure from the ear pads against the frames, but this is common with most over-ear headphones. Overall, the HD 660S2 ranks among the most comfortable headphones in its price range.

Impedance, Amplification, and Source Requirements

The HD 660S2 has an impedance of 300 ohms and a sensitivity of 104 dB SPL at 1V. These numbers tell you something important: this headphone needs power. You cannot just plug it into your phone’s headphone jack and expect great results.

A dedicated headphone amplifier or a quality DAC/amp combo will bring the HD 660S2 to life. Popular pairings include the Schiit Magni/Modi stack, the iFi Zen DAC, and the Topping DX5. Desktop audio interfaces also work well as sources.

With proper amplification, the HD 660S2 sounds dynamic and full. Without it, the bass feels thin and the overall volume may be too low. Invest in a decent amp if you plan to buy these headphones. Budget around $100 to $200 for a solid entry-level setup.

Who Should Buy the Sennheiser HD 660S2?

The HD 660S2 suits a specific type of listener. If you enjoy warm, natural sound with a focus on midrange clarity, this headphone is an excellent match. Vocal lovers, jazz fans, and acoustic music enthusiasts will find a lot to enjoy here.

It also works well for casual critical listening at home. If you want to sit back, relax, and appreciate the details in your favorite albums, the HD 660S2 delivers that experience beautifully. It rewards patience and attention.

This is not the best pick for gaming or movies, though. The intimate soundstage limits spatial awareness in competitive games. And if you listen to bass-heavy genres almost exclusively, you might prefer a planar magnetic alternative. The HD 660S2 is a specialist, not a generalist. It does its job with grace.

Sennheiser HD 660S2 vs. HD 660S: What Changed?

The HD 660S2 builds on the original HD 660S in several key ways. The most significant change is the new transducer design. Sennheiser used a soft diaphragm paired with a steel mesh damping element. This replaces the previous Duofol diaphragm.

The impedance jumped from 150 ohms to 300 ohms. This aligns the HD 660S2 with the HD 600 and HD 650. It also means you need a stronger amp to drive it. The resonant frequency dropped from 110 Hz to 70 Hz, which explains the improved bass extension.

In terms of sound, the HD 660S2 is warmer and more relaxed than the HD 660S. The original had a more forward, brighter character. The HD 660S2 trades some of that energy for deeper bass and smoother treble. Which one you prefer depends on your taste. Both are excellent headphones.

Pricing and Value for Money in 2026

The Sennheiser HD 660S2 launched at an MSRP of around $599 to $679. That price drew criticism from many reviewers and buyers. At launch, it was hard to justify the cost over the cheaper HD 650 or HD 600, which offered similar performance.

Fast forward to 2026, and the picture looks much better. Street prices have dropped to around $400 to $450 on Amazon and other retailers. Sweetwater recently listed it at $449 with instant savings. At this price, the HD 660S2 is a strong value proposition.

For around $400, you get a refined, well-tuned open-back headphone from one of the most respected brands in audio. It competes well against the Beyerdynamic DT 900 Pro X and HiFiMAN Sundara at similar prices. If you can find it on sale for under $400, it becomes an easy recommendation.

Pros and Cons of the Sennheiser HD 660S2

Every headphone has strengths and weaknesses. The HD 660S2 is no different. Here is a quick summary to help you decide.

Pros: The sound quality is warm, natural, and detailed. Sub-bass extension is a real upgrade over previous models. Comfort is outstanding for long sessions. Build quality is reliable and proven. The price has dropped significantly since launch.

Cons: The 300-ohm impedance means you need a dedicated amp. The soundstage is intimate and may feel narrow to some listeners. Plastic construction feels less premium than competitors at this price. Treble can sound slightly recessed if you prefer a brighter signature. It is not the best option for gaming or bass-heavy music.

Overall, the pros outweigh the cons for most audiophile listeners. The HD 660S2 does what it does very well. It just does not try to do everything.

Final Verdict: Should You Buy the Sennheiser HD 660S2 in 2026?

The Sennheiser HD 660S2 remains a solid choice for audiophile listeners in 2026. It offers warm, natural sound with excellent midrange clarity and improved bass extension. Comfort is top-tier. Build quality is dependable.

At its current street price of $400 to $450, it delivers much better value than it did at launch. If you already own a decent headphone amp and you love vocal-rich, detail-oriented music, the HD 660S2 will make you happy. It is a headphone that rewards careful listening.

If you want wider soundstage or more bass impact, consider the alternatives we listed above. But for pure midrange magic and long-session comfort, the Sennheiser HD 660S2 is hard to beat.

Frequently Asked Questions

Is the Sennheiser HD 660S2 good for gaming?

The HD 660S2 can work for casual gaming, but it is not ideal for competitive play. Its intimate soundstage limits spatial awareness. Footstep detection and directional cues are average compared to gaming-focused headphones. For dedicated gaming, a wider-soundstage option like the Beyerdynamic DT 900 Pro X is a better fit.

Does the HD 660S2 need an amplifier?

Yes. The HD 660S2 has a 300-ohm impedance. It requires a dedicated headphone amplifier or a strong DAC/amp combo to reach its full potential. Plugging it into a phone or laptop will result in low volume and thin sound. Budget at least $100 for a quality entry-level amp.

How does the HD 660S2 compare to the HD 650?

The HD 660S2 offers better sub-bass extension and slightly more detail than the HD 650. The HD 650 has a warmer, more laid-back midrange with less treble energy. Both share the same 300-ohm impedance. The HD 650 is often cheaper and remains a fan favorite. Your choice depends on whether you value the added bass depth of the HD 660S2.

Is the Sennheiser HD 660S2 worth it in 2026?

At its current price of around $400 to $450, the HD 660S2 is a strong buy. It was overpriced at launch, but the recent price drops make it a competitive option in the mid-range audiophile headphone market. If you enjoy warm, natural sound and have a proper amp, it is absolutely worth it.

Can I use the HD 660S2 for music production?

The HD 660S2 can work for music production, but it is not a neutral reference headphone. Its warm tuning and recessed treble may color your mixes. For mixing and mastering, a flatter option like the Beyerdynamic DT 900 Pro X or Sennheiser HD 490 Pro is more suitable. The HD 660S2 is better suited for enjoyment-focused listening.

What cable does the Sennheiser HD 660S2 use?

The HD 660S2 uses a detachable cable with dual-sided entry. The connectors at the ear cups are proprietary Sennheiser connectors. The included cable terminates in a 6.35mm (1/4-inch) plug with a 3.5mm adapter included. Aftermarket cables are widely available if you want to upgrade or customize.

Last update on 2026-03-27 / Affiliate links / Images from Amazon Product Advertising API