Is Sennheiser HD 660S2 Worth It? Honest Review (2026)
A balanced look at the HD 660S2's strengths, weaknesses, and who should buy it in 2026.
Quick Decision
Buy it if you already own a decent headphone amp and want a warm, open-back sound with real bass weight. Skip it if you don't have an amp or expect a huge soundstage, because the HD 600 and Sundara meet those needs for less. At street prices near $499, it rewards listeners who will actually use its low-end and midrange strengths.
Best if you...
- Home listeners with a dedicated headphone amp
- Fans of acoustic, jazz, rock, and vocal music
- Listeners upgrading from HD 600 or HD 650 who want more bass
Skip it if you...
- Phone-only listeners without an external amp
- Bassheads who need heavy sub-bass for EDM and hip-hop
- Shared offices or bedrooms that need sound isolation
If you are comparing open-back headphones around $500, the Sennheiser HD 660S2 almost certainly came up. It is one of the few models that tries to fix the biggest complaint about the beloved HD 600 series — the polite, lean bass — without sacrificing the midrange that made those headphones famous. This guide covers what the HD 660S2 does well, where it falls short, and how it stacks up against the main alternatives. We also look at accessories that matter and help you decide if it belongs on your desk. You can find the Sennheiser HD 660S2 on Amazon to check current pricing while you read.
About the Sennheiser HD 660S2
An open-back dynamic headphone from Sennheiser's 600 series, tuned to deliver deeper bass while keeping the natural midrange the series is famous for. It is designed for home listening with a headphone amplifier and suits audiophiles who want one reliable, musical pair.
Key Specifications
- Type
- Open-back dynamic over-ear
- Driver
- 42mm dynamic
- Weight
- Approximately 260g
- Cable(s)
- 1.8m with 6.3mm plug; 3m with 4.4mm Pentaconn (balanced)
- Impedance
- 300 ohms
- Sensitivity
- 104 dB (1 kHz / 1 Vrms)
- Frequency Response
- 8 Hz – 41,500 Hz
Overview
The HD 660S2, released in early 2023, is an evolution of the HD 660S and the broader HD 600 family. It uses a 42mm dynamic driver with a lighter voice coil and an aluminum short-circuit ring, which Sennheiser says improves transient response and adds bass presence. The result is a headphone that sounds familiar to anyone who knows the 600 series, but with a fuller low end and a touch more detail. It sits between the affordable HD 600 and the flagship HD 800 S, aimed at listeners who want a single premium open-back for detailed home listening. The typical setup uses a desktop amplifier rather than a phone or laptop. Check the current listing on Amazon for street pricing, which often lands near $499 despite the $599 MSRP.
Pros
The HD 660S2 earns its reputation on a handful of strengths: deep bass for an open-back, a natural and engaging midrange, all-day comfort, and a design that can be repaired rather than replaced. These are the traits that make it feel like a long-term purchase rather than a disposable gadget.
Pro 1: Deep, Controllable Bass for an Open-Back
The HD 660S2 is the first Sennheiser 600-series model to genuinely address the 'polite bass' complaint. Sennheiser's published frequency response extends from 8 Hz to 41.5 kHz, and measurements reported by RTINGS show more sub-bass output than the HD 660S and HD 650. The low end is present without bleeding into the midrange.
For listeners coming from the HD 600, the extra weight is obvious on acoustic bass, kick drums, and synth textures. It doesn't turn the HD 660S2 into a basshead headphone, but it makes rock and electronic music sound fuller while keeping the clarity that defines the series.
Pro 2: Natural, Intimate Midrange
The HD 660S2 keeps the vocal-forward midrange that made the HD 600 and HD 650 classics. Male and female vocals sit centered and close, with no harsh upper-mid peak. This is a headphone for people who care more about hearing the singer than hearing the recording.
It works well for acoustic music, jazz, folk, and any genre where instrument textures matter. The midrange is smooth enough for long sessions but detailed enough to reveal finger noise and room ambience.
Pro 3: Lightweight, Long-Session Comfort
According to Sennheiser's spec sheet, the HD 660S2 weighs about 260 grams, which is light for an open-back with this build quality. The padded headband and velour earpads distribute pressure evenly, and the clamping force is moderate out of the box.
This is one of the most comfortable headphones in the price bracket. Most head sizes should find the fit workable, and the low weight means you can wear it for a full afternoon of listening without needing a break.
Pro 4: Detachable Cables and Replaceable Pads
The HD 660S2 uses a 2-pin connector at each earcup, so cables are easy to swap. Sennheiser includes a 1.8m cable with a 6.3mm plug and a 3m cable with a 4.4mm Pentaconn balanced plug, giving you both single-ended and balanced options out of the box.
The earpads are also replaceable, which matters for a headphone you may own for a decade. A pair of fresh pads restores both comfort and bass seal, and third-party options are easy to find.
Pro 5: Fast, Natural Transients
The aluminum short-circuit ring in the driver is designed to reduce mechanical distortion, and the effect is audible in cymbal crashes, guitar attacks, and percussion. Treble detail is resolved without the piercing brightness found on many analytical headphones.
This balance between warmth and clarity makes the HD 660S2 easy to listen to at high volumes and tiring at none. It is a headphone that rewards focused listening without punishing you when you just want to zone out.
Pro 6: A Good Match for Quality Amplifiers
At 300 ohms, the HD 660S2 is an ideal load for many desktop amplifiers, especially OTL tube designs that favor higher impedance loads. You don't need a huge amp, but a clean source lets the bass stay firm and the transients stay crisp.
If you already own a dedicated amp, the HD 660S2 will get along with it immediately. If you are building a system from scratch, the amp cost should be part of your budget, but it also means the headphone scales well when you upgrade your electronics later.
Cons
No headphone is perfect, and the HD 660S2 makes some clear trade-offs. The biggest are its amplifier requirement, the open-back leakage, and a price that sits above several very good alternatives. Here's where it disappoints and who feels it most.
Con 1: You Need an Amplifier to Hear Its Best
The HD 660S2's 300-ohm impedance requires voltage that most phones and laptop headphone jacks don't provide. Plugged straight into a laptop, it will sound thin, bass-light, and undynamic. A dedicated amp in the $75–$150 range fixes this, but it raises the total cost of the system.
This isn't a problem if you already have a desktop setup, but it is the main reason the HD 660S2 won't work for casual portable listening.
Con 2: Open-Back Design Leaks Sound
Because it is an open-back headphone, the HD 660S2 radiates audio through the rear of the drivers. People in the same room will hear your music, and you will hear their conversations. This makes it unsuitable for open offices, libraries, dorms, or late-night listening next to someone sleeping.
If you need isolation, a closed-back model is the better tool. The HD 660S2 is strictly a private-space headphone.
Con 3: Intimate, Not Immersive, Soundstage
The HD 660S2 places instruments in a focused, close-up layout rather than a huge concert hall. That is excellent for vocals, but it can be disappointing if you want a wide, airy presentation for orchestral or ambient music.
Alternatives like the Hifiman Sundara offer a larger sense of space, and the HD 800 S takes that much further. If soundstage width is your priority, the HD 660S2 is not the best choice.
Con 4: Sub-Bass Is Still Restrained by Basshead Standards
The extra bass in the HD 660S2 is welcome, but it is not a V-shaped tuning. The deepest sub-bass still rolls off, so very sub-heavy EDM, hip-hop, and modern pop won't have the chest-thump of closed-back or planar headphones.
You can EQ it, but doing so requires headroom from a good amp. If you mostly listen to bass-heavy genres, look at a planar model or a closed-back with a bass boost.
Con 5: Premium Price Next to Strong Sennheiser Alternatives
With an MSRP of $599 and typical street pricing around $499, the HD 660S2 costs roughly $200 more than the HD 600 or HD 650. The improvements are real but incremental: more sub-bass, a touch more treble detail, and slightly better imaging.
For neutral-sound purists, the HD 600 is still the better value. The HD 650/HD 6XX offers much of the same warmth for considerably less.
Con 6: No Case and Oversized Connectors
Both included cables end in large 6.3mm or 4.4mm plugs, so simple portable use requires a 6.3mm-to-3.5mm adapter. There is also no carrying case in the box, which is surprising at this price point.
These issues don't affect desktop listening, but they add small annoyances if you ever want to move the headphone between rooms or take it somewhere.
👍 Who It's For
The HD 660S2 is for the home listener who already has a headphone amplifier and wants a warm, musical open-back with real bass weight. It's also for audiophiles who love the HD 600 family's midrange but need more low-end presence for rock, jazz, and electronic music. If you listen to vocals for hours and want a comfortable, serviceable headphone you can keep for a decade, this is a strong fit.
It works especially well in a dedicated listening room or quiet home office where background noise is low. The 300-ohm design pairs beautifully with tube amps, and the detachable cables make it easy to adapt to balanced or single-ended setups.
👎 Who Should Avoid
If you don't already own an amplifier, the HD 660S2 is a hard sell. The extra cost of a decent amp pushes the total system past $700, and direct phone/laptop use will leave you underwhelmed. Bassheads who want heavy sub-bass and fans of very wide, cinematic soundstages should also look elsewhere.
The open-back design is a dealbreaker for shared spaces, and the premium price is harder to justify when the HD 600 and HD 650 deliver much of the character for hundreds less. If you need a portable or closed-back headphone, or your priority is maximum value, this one is not for you.
See today's Sennheiser HD 660S2 price and available configurations on Amazon.
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Alternatives to Consider
| Product | Choose Sennheiser HD 660S2 if... | Choose the alternative if... |
|---|---|---|
| Sennheiser HD 600$200 more expensive | You want the extra bass weight and a slightly warmer, more engaging sound than the HD 600's neutral tuning. | You prefer a purely neutral reference response and want to save about $200. |
| Hifiman Sundara$200 more expensive at MSRP | You want a forgiving midrange and more bass warmth than the Sundara's bright, detail-forward presentation. | You want faster planar transient response and deeper sub-bass for the same price. |
| Beyerdynamic DT 900 Pro XAbout $250 more expensive | You want a high-impedance design that pairs well with a dedicated amplifier and presents vocals with Sennheiser's classic smoothness. | You need to drive your headphones from a laptop, phone, or interface without an external amp, and you want a brighter, punchier tuning. |
The biggest alternative is the Sennheiser HD 600, which is often available under $300. It has a leaner, more neutral low end and is the better choice if you want an uncolored reference. The HD 650/HD 6XX is warmer and even more affordable, but it doesn't extend as far down as the HD 660S2. For a planar option, the Hifiman Sundara is often available for around $299 and delivers faster transients and deeper sub-bass, though its tuning is brighter and less forgiving.
If you want a dynamic headphone that runs well without an amp, the Beyerdynamic DT 900 Pro X sells for about $250 and works directly from laptops and interfaces. All four are worthy rivals, but the HD 660S2 offers the most refinement if you already have the electronics to drive it properly.
Is it worth the price?
At approximately $499, the HD 660S2 is worth it for listeners who have a dedicated amp and value the Sennheiser midrange with more low-end weight. Compared to the $299 HD 600 or Hifiman Sundara, the value is harder to justify unless you specifically want the 660S2's tuning and build. If you are new to audiophile headphones and need to buy an amp as well, the total cost approaches $700, which shifts the verdict toward the alternatives.
📝 Bottom Line
The Sennheiser HD 660S2 is the right choice for home listeners who already have a headphone amplifier and want the HD 600-series midrange with real bass weight. It is not a radical redesign; it is a careful tuning that addresses the most common complaint about the HD 600 and HD 650 without losing the natural, vocal-forward quality that made them classics.
The strengths are clear: deep but controlled bass, a smooth and detailed midrange, a comfortable ~260g build, and a serviceable design with detachable cables and replaceable pads. The main drawbacks are the need for an amp, a soundstage that stays intimate, and a price that sits above the HD 600 and HD 650. If you can accept those trade-offs, this is one of the most musically satisfying open-back headphones you can buy without stepping into flagship territory.
Our bottom line: buy the HD 660S2 if you value vocal intimacy and want the HD 600-series sound with more low-end presence, especially for rock, jazz, and acoustic music. Skip it if you're on a tight budget, lack an amplifier, or need a wide, immersive soundstage — in those cases, the HD 600, Hifiman Sundara, or Beyerdynamic DT 900 Pro X will serve you better for less. Before deciding, check the current listing on Amazon to see where street pricing lands.
Check current Sennheiser HD 660S2 availability and bundle options on Amazon.
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Frequently Asked Questions
Quick Summary
Key Pros
- ✓Deeper, more controlled bass than the HD 600/HD 650 for an open-back
- ✓Natural, vocal-forward midrange with no harsh treble
- ✓Lightweight ~260g frame with plush velour earpads
- ✓Detachable 6.3mm and balanced 4.4mm cables, replaceable earpads
- ✓Fast transients and good instrument separation
Key Cons
- ✗Requires a dedicated headphone amp to sound its best
- ✗Open-back design leaks sound in and out
- ✗Soundstage is intimate rather than expansive
- ✗Sub-bass still restrained for bass-heavy genres
- ✗Premium pricing versus the HD 600/HD 650
Ratings
Best For
- →Home listeners with a dedicated headphone amp
- →Fans of acoustic, jazz, rock, and vocal music
- →Listeners upgrading from HD 600 or HD 650 who want more bass
- →People who plan to keep one headphone for many years