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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
If you want the richer, more customizable music-listening experience for library study sessions, choose Sony WH-CH520; if you need a waterproof, open-ear set that keeps you aware of your surroundings and plays even without a phone, choose kelankeke Bone Conduction Headphones. I'll walk you through why those two designs pull in such different directions — and which one fits the way you actually listen.
• Sony WH-CH520 biggest strength: Up to 50 hours of playback with fast USB-C quick charging (about 90 minutes of playtime from a 3-minute top-up), plus EQ Custom and DSEE sound tuning via Sony's app.
• Sony WH-CH520 biggest trade-off: It's a wireless-only, over-ear design with no headphone jack, no water-resistance rating, and no active noise cancellation.
• kelankeke Bone Conduction Headphones biggest strength: IPX8 waterproofing plus a built-in 32GB MP3 player — up to 8,000 songs stored on the headphones and roughly 10 hours of playback, no phone required.
• kelankeke Bone Conduction Headphones biggest trade-off: Open-ear bone conduction means you trade deep, isolating bass for environmental awareness, and Bluetooth doesn't work underwater.
• Choose Sony WH-CH520 if you mainly want long-battery music, podcasts and calls in a quiet indoor setting like a library.
• Choose kelankeke Bone Conduction Headphones if you want one pair for swimming, running and sweaty workouts where water and staying aware matter more than thumping bass.
The WH-CH520 is built around one idea: keep music going for a very long time without fuss. Sony rates the battery at up to 50 hours, and a 3-minute quick charge buys you roughly 90 minutes of playback — that's the kind of headphone you can toss in a bag, forget to charge for days, and still have working.
Who should buy it? Someone who listens on a phone or laptop indoors, wants hands-free calls through the built-in mic, and likes the convenience of pairing two Bluetooth devices at once so a call can interrupt a laptop video without re-pairing. Swivel joints make it fold flat for a backpack, and voice-assistant support plus a find-my-device feature round out the everyday experience.
Who should skip it? Anyone who swims, sweats heavily, or needs to hear traffic and surroundings. There's no water-resistance rating here, no wired jack as a backup, and no active noise cancellation — it's a comfort-and-battery play, not a rugged one.
kelankeke Bone Conduction Headphones: Who It's For
The kelankeke set is a very different animal. It sits outside your ear canal and sends sound through bone conduction, which means your ears stay open. That's the whole point: you keep hearing the world while music plays. At roughly 28 grams, it's light enough that the open-ear design barely registers, which matters for long runs or bike rides.
The headline feature is the IPX8 waterproof rating — fully sealed against water, sweat, rain and dust. But there's a catch worth knowing before you buy: Bluetooth doesn't transmit underwater, so for swimming you switch to the built-in MP3 mode by double-clicking the power button. That mode taps 32GB of onboard storage holding up to 8,000 songs across MP3, WMA, FLAC, APE and WAV formats. You load tracks by connecting the magnetic charging cable to a computer, where the headphones show up as USB storage.
Battery life lands around 10 hours, with a full charge in about 2 hours via that same magnetic cable. Bluetooth 6.0 gives a stable connection up to roughly 10 meters, and passive noise cancellation is the only kind on offer — unsurprising for an open design. Controls are physical buttons rather than touch, which is easier to operate with wet or gloved hands.
Side-by-Side: Which Should You Choose?
• Best for long battery life → Sony WH-CH520 (up to 50 hours vs. about 10 hours).
• Best for sound customization → Sony WH-CH520 (EQ Custom presets and DSEE for compressed files).
• Best for swimming and water → kelankeke (IPX8 waterproofing; Sony has no water rating).
• Best for phone-free listening → kelankeke (32GB onboard MP3 storage for up to 8,000 songs).
• Best for staying aware of your surroundings → kelankeke (open-ear bone conduction design).
• Best for calls and multi-device switching → Sony WH-CH520 (built-in mic and two-device Bluetooth pairing).
• Best for lightweight, secure fit during workouts → kelankeke (about 28 g, open-ear, silicone build).
• Best for quiet indoor focus → Sony WH-CH520 (over-ear seal blocks more of the room).
For a library-focused listener — someone studying, reading or working quietly and wanting one pair to carry music and podcasts through a long day — I'd buy the Sony WH-CH520. In my opinion the 50-hour battery, EQ Custom tuning, DSEE processing and over-ear seal make it the stronger pure music headphone, and that's the use case this comparison is really about. The kelankeke set wins clearly for anything wet or athletic, but for indoor listening its open-ear design is a limitation rather than a feature. If you're torn, decide by environment first, then check the current price on Amazon before committing.
FAQ
how to make headphones music louder
Check the volume on both the source device and the headphones themselves, and make sure any app-level volume limiter is off. On the Sony WH-CH520 you can also adjust sound character through EQ Custom in Sony's app, which changes the tonal balance rather than the raw loudness ceiling.
how to fix stereo headphones
Start with the basics: confirm the Bluetooth connection is stable, charge the battery, and re-pair the device. On the kelankeke set, if audio stops after switching modes, the manufacturer's steps are to verify song formats (MP3, WMA, FLAC, APE or WAV), confirm the computer recognizes the headphones, then delete and re-copy the tracks.
how to test stereo headphones
how to make stereo headphones
You can't convert a finished headphone into a stereo pair, but you can make a set behave like one for you: pair two Bluetooth devices on the Sony WH-CH520, or load your own tracks onto the kelankeke's 32GB storage so it plays as a standalone stereo music player without any phone attached.
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