How We Research
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
If you want a closed-back, isolating studio monitor that keeps your music contained and outside noise out for study, choose Superlux HD661; if you need an open-back planar magnetic headphone with a brighter, more neutral tuning and a much wider frequency range for critical listening, choose DROP + HIFIMAN HE5XX. Both are wired over-ear designs built for people who care about a flat, honest frequency response rather than a bass-boosted consumer sound. The choice really comes down to whether you need isolation for study or openness for detail.
• Superlux HD661 biggest strength: A closed-back, sealed design with a 68Ω impedance and 102dB sensitivity, so it isolates you from room noise and is easy to drive from modest sources.
• Superlux HD661 biggest trade-off: Its 10Hz–20,000Hz range and dynamic driver are honest but limited compared to a planar design, and the closed cup gives a narrower, more intimate soundstage.
• DROP + HIFIMAN HE5XX biggest strength: A planar magnetic driver covering 15Hz–50,000Hz with a brighter, more neutral take on the classic HE500 tuning, plus remarkably light 354g construction.
• DROP + HIFIMAN HE5XX biggest trade-off: An open-back design leaks sound both ways, so it is not the headphone for a noisy dorm, library, or shared study space, and its 18Ω impedance means it rewards a decent source.
• Who the HD661 is for: Students and studio users who need isolation and a sealed, no-fuss monitor.
• Who the HE5XX is for: Listeners who want an open, airy, neutral-sounding planar headphone for quiet rooms and detailed listening.
The HD661 is a closed-back studio monitor built around a 40mm dynamic driver with a neodymium magnet. The specs tell a story of a practical tool: 68Ω impedance, 102dB sensitivity at 1kHz, and a frequency band of 10Hz to 20,000Hz. That sensitivity figure matters for real-world use, because it means the HD661 does not demand a powerful amplifier to reach a usable volume — a laptop, phone, or basic interface will drive it fine.
Who should buy it? Anyone who needs a sealed, isolating over-ear for study, tracking, or monitoring where background noise is a factor. Who should skip it? If you chase the widest soundstage and the most extended treble detail, the closed dynamic design will feel boxed-in next to a planar open-back. It also lists active noise cancellation and Bluetooth under its controls, but the core identity here is a wired, sealed monitor — treat the wireless mention with caution and buy it for its wired strengths.
DROP + HIFIMAN HE5XX: Who It's For
The HE5XX is a planar magnetic, open-back over-ear headphone from Drop's collaboration with HIFIMAN — their sixth together. The headline design story is weight and driver tech: a dual-sided planar magnetic design with stronger double magnets and 2-micron-thick Nano Diaphragm membranes, which makes it about 30 percent lighter than the legacy HE500. At 354g it is genuinely light for a planar, and the aluminum, faux leather, and plastic build keeps it comfortable for long sessions.
The tuning is described as a brighter, more neutral take on the HE500 Series sound, with a frequency range of 15Hz to 50,000Hz and an 18Ω impedance. That low impedance plus improved efficiency makes it easier to drive than older planars, and it is wired to accept a balanced cable if you want to push it further. A 6.35mm-to-3.5mm adapter is included, along with a 1-year manufacturer's warranty.
Who should buy it? Listeners who want an open, airy presentation, a neutral tonal balance, and the speed of a planar driver, and who listen in a quiet room where sound leakage does not matter. Who should skip it? Anyone who needs isolation. Open-back means sound goes out and noise comes in, so it is a poor fit for noisy study spaces, libraries, or shared rooms. If transparency and outside awareness matter to you, this is the kind of open design that gives it naturally — but it works both directions.
• Best for study in a noisy space → Superlux HD661. The sealed, airtight closed-back design blocks outside noise and keeps your audio private.
• Best for a quiet room and critical listening → DROP + HIFIMAN HE5XX. Open-back, planar, and neutral, with far more treble extension.
• Best frequency range → DROP + HIFIMAN HE5XX. 15Hz–50,000Hz versus the HD661's 10Hz–20,000Hz.
• Easiest to drive from a phone or laptop → Superlux HD661. 102dB sensitivity and 68Ω are forgiving of modest sources.
• Best for long sessions comfort-wise → DROP + HIFIMAN HE5XX. 354g with ultralight components designed for fit and comfort.
• Best for tracking and monitoring where isolation is required → Superlux HD661. That is the exact use case its sealed design targets.
• Best for a balanced cable upgrade path → DROP + HIFIMAN HE5XX. It is wired to work with a balanced cable.
• Best bundled accessories for flexibility → Superlux HD661. Two cable lengths, an adapter, a clip, and a pouch out of the box.
If I were buying for study — especially in a space with any background noise — I would choose the Superlux HD661. Its sealed closed-back design, 102dB sensitivity, and sensible 68Ω impedance make it the more practical everyday tool, and the bundled cables and adapter add real value. I would pick the DROP + HIFIMAN HE5XX instead if I listened mainly in a quiet room and wanted a neutral, open planar sound with a much wider frequency range. In my opinion the HD661 wins for study, and the HE5XX wins for pure critical listening.
FAQ
For study, isolation usually matters most, which points to a closed-back design like the Superlux HD661 rather than an open-back like the HE5XX. A sealed over-ear keeps room noise out and your audio in, so you can focus without disturbing anyone.
I would not recommend open designs like the HE5XX for noisy study spaces, because they let sound in and out. If you specifically need awareness of your surroundings, an open design helps, but it is the wrong tool for blocking distraction.
The HE5XX is an open-back headphone, so it naturally lets ambient sound through — closer to a passive transparency effect than an active feature. The HD661 goes the other way with a sealed, isolating design, which suits focused study better.
As an Amazon Associate I earn from qualifying purchases.
We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.
When you buy through links on this page, we may earn a commission from qualifying purchases at no extra cost to you.
Amazon and the Amazon logo are trademarks of Amazon or its affiliates. This site is an independent third-party review and is not affiliated with, endorsed by, or sponsored by Amazon or the product brands mentioned.
See also: E-filliate DEWALT Heavy Duty vs KETAKY Plus USB C, bone conduction headphones waterproof, Gsangoo USB C Headphones vs AILKIN USB C Headphones, Altec Lansing NanoBuds Sport 2.0 vs OTRBCOY True Open Ear