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If you want a complete, ready-to-wear wired in-ear monitor with a natural, open-sounding presentation and a fully transparent shell, choose Moondrop Quarks Earphone Closed; if you need to revive a pair of Audio-Technica open back monitor headphones with fresh, sealed protein-leather cushions, choose Xinyuekj Replacement Ear Pads.
• Moondrop Quarks — biggest strength: a complete, self-contained IEM with a 6 mm composite-magnetic dynamic driver, a 16 ohm / 116 dB spec that's easy to drive, and a shell you can see straight through.
• Moondrop Quarks — biggest trade-off: it's a closed in-ear design, so it isolates you from the room rather than letting the room in, and it's a single 3.5 mm wired connection with no wireless option.
• Xinyuekj Replacement Ear Pads — biggest strength: protein leather over memory foam that seals the ear and boosts bass and isolation on compatible Audio-Technica models, with a wipe-clean surface.
• Xinyuekj Replacement Ear Pads — biggest trade-off: it only fits a specific list of Audio-Technica models, and the sealed design changes the sound signature of an open back monitor rather than preserving it.
• Who each is for: pick the Quarks if you want a new, complete earphone; pick the Xinyuekj pads if you already own compatible Audio-Technica open back monitor headphones and want to refresh the fit and sound.
The Quarks is a finished product, not a part. It arrives as a wired in-ear monitor built around a 6 mm dynamic driver with a composite magnetic micro diaphragm, and it's tuned with a frequency response curve the brand says was refined over two years of repeated adjustments to sit close to the HRTF (head-related transfer function) curve. In plain terms, that tuning choice is meant to produce a natural, open-feeling soundstage instead of a boxy, in-your-head presentation. There's a moderate bass lift too, which the spec sheet frames as making the sound more musical and giving the ambience a fuller body.
The physical design is the other half of the story. The shell is fully transparent polycarbonate, so you can literally see the driver and the acoustic structure inside — a small, rounded, contemporary-looking thing that the brand leans into as a "geek" aesthetic. It's compact enough to wear in a few different ways, and the internals include a patented anti-blocking sound damping design plus a double-damping structure, which matters because damping is what keeps a small driver from getting shouty or harsh when it's sealed into your ear.
Who should buy it? Someone who wants one purchase, one box, no assembly: a wired 3.5 mm earphone with an inline media control and touch interface, a 20 Hz–20 kHz range, and an impedance/sensitivity pairing (16 ohm, 116 dB) that a phone or a laptop dongle can drive without a dedicated amp. If you commute, work in a shared space, or just want something small that disappears in a pocket, the closed in-ear format is the point — it isolates you from the room, and the sound-isolation control is built around exactly that.
Who should skip it? If you specifically want the airy, leaky, "hear the room" character of an open back monitor headphone, this isn't that. It's an IEM. And if you want wireless, there's no Bluetooth here — it's wired, full stop. Six-month warranty coverage is also on the shorter side, so treat it as a straightforward daily driver rather than a lifetime purchase.
This is a maintenance and upgrade part, and you should only consider it if you own one of the listed headphones: the Audio-Technica ATH-AD900X, AD1000X, AD2000X, AD700X, A500, AD500X, A500X, A700, and A900X. That compatibility list is the whole ballgame — check your model number before anything else, because these pads are cut for those housings and nothing else.
What they actually do is swap the stock open velour for a sealed protein-leather cushion over high-density memory foam. That's a meaningful acoustic change, not just a cosmetic one. The brand is upfront that the sealed-back design creates a tighter seal than the original open-air pads, which reduces sound leakage and ambient noise and pushes up bass presence. So on an open back monitor headphone, you're trading some of that classic open, breathable character for a more closed-in, more bass-forward, more isolating feel. Some people want exactly that; some people will hate it. Worth knowing before you commit.
The comfort argument is real, though. Protein leather is skin-friendly, more durable than velour, and far easier to clean — a damp cloth handles it, and the sweat-resistant surface resists moisture buildup. Memory foam distributes pressure and cuts the hot spots that show up in long sessions, whether that's marathon gaming, mixing, or just a long listening night. Installation is tool-free: pull the old pads, snap the new ones in, done in minutes. The 90-day warranty is short, which is typical for a consumable like this.
Who should buy it? Anyone whose compatible Audio-Technica pads are flattened, flaking, or just unpleasant, and who wants a cleaner, more isolating, bassier result. Who should skip it? Anyone who doesn't own a listed model, and anyone who loves their open back monitor sound exactly as it is — because these pads will change it.
• Best for a complete, ready-to-use product → Moondrop Quarks Earphone Closed. It's a whole earphone, not a component.
• Best for repairing or upgrading headphones you already own → Xinyuekj Replacement Ear Pads. It exists purely to refresh compatible Audio-Technica models.
• Best for isolation from your surroundings → Moondrop Quarks Earphone Closed. The closed in-ear shell and sound-isolation design block the room out.
• Best for keeping the open, airy character of an open back monitor → neither, strictly speaking. The pads deliberately seal things up; the Quarks is an IEM. If open-back airiness is the goal, you want to stay with open pads.
• Best for long-session comfort → Xinyuekj Replacement Ear Pads. Memory foam and protein leather are built for pressure distribution over hours.
• Best for easy cleaning and hygiene → Xinyuekj Replacement Ear Pads. Wipe-clean leather beats velour, hands down.
• Best for low-hassle phone/laptop use → Moondrop Quarks Earphone Closed. 16 ohm and 116 dB means it plays loud off modest sources.
• Best for bass emphasis on an existing pair → Xinyuekj Replacement Ear Pads. The seal is what adds the low-end weight.
• Best for a small, pocketable wired setup → Moondrop Quarks Earphone Closed. Compact transparent shell, 3.5 mm jack, inline controls.
In my opinion, these two aren't really competitors — they solve different problems, and the right answer is whichever problem you actually have. If you need an earphone, I'd buy the Moondrop Quarks Earphone Closed: it's complete, easy to drive, tuned for a natural and open-feeling presentation, and the transparent shell is genuinely fun. If you already own a compatible Audio-Technica open back monitor headphone and your pads are shot, I'd buy the Xinyuekj Replacement Ear Pads — just go in knowing they'll seal the sound up and add bass rather than preserve the stock openness. Check the current price on Amazon for whichever one matches your situation before you commit.
how to open back headphones work
Open back headphones use housings with vents or grilles that let air move in and out of the earcups. That airflow gives the sound a wider, more natural, less enclosed feel, but it also lets sound leak out and room noise leak in. The Xinyuekj pads are designed for exactly this style of headphone — and sealing them up changes that behavior.
what is open back studio headphones
They're headphones built for mixing and critical listening where you want a spacious, uncolored presentation and some awareness of your surroundings. Models like the Audio-Technica ATH-AD900X and AD700X are in this family. Their stock velour pads are part of that open design, which is why swapping in sealed protein-leather pads alters the sound.
what are the best open back headphones
There's no single answer — it depends on your source, your comfort needs, and whether you want isolation. What I can say is that if you own a compatible Audio-Technica open back monitor, the Xinyuekj pads are a practical way to restore comfort and add bass, while the Moondrop Quarks is a better pick if you'd rather have a complete, isolating in-ear setup instead.
are open back headphones better
Better for some things, worse for others. They tend to sound more spacious and natural, but they isolate poorly and leak sound, so they're a bad fit for commuting or noisy shared spaces. If you need to block the world out, a closed in-ear like the Moondrop Quarks Earphone Closed is the more sensible choice.
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See also: Xinyuekj Replacement Ear Pads vs Generic 2-Pack, SINOWO Ear Cushions vs SparkFeng Replacement Ear Pads, HAOMUK Replacement Ear Pads vs KODAPAGE Replacement Ear Pads