We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-01 · 7 min read · Independent comparison
If you want a pair of music headphones you can wear in the pool, in the rain and on a run while still hearing traffic, choose PSIER Bone Conduction Headphones; if you need headphones built around sleep — something that blacks out light, feels fine against a pillow and plays soft audio all night — choose LC-dolida Sleep Headphones. These two are not really competitors. They are two different answers to the question "what should I put on my head to listen to music?" and the honest answer depends on when you listen.
• PSIER's biggest strength: true bone conduction with 14mm drivers, an IPX8 rating for submersion up to two meters for an hour, and 32GB of built-in MP3 storage — roughly 4,000 songs you can play with no phone nearby, switched with a double click.
• PSIER's biggest trade-off: open-ear by design, so there is no noise isolation at all, and the control scheme is touch-based with no noise control features listed. Out of the water you switch back to Bluetooth manually.
• LC-dolida's biggest strength: a genuine 3-in-1 design — full blackout eye mask, Bluetooth 5.4 headphones and 15+ hours of playtime — with slim padded speakers that don't press hard on your ears when you lie on your side.
• LC-dolida's biggest trade-off: it is a sleep mask first. There is no IP rating, no MP3 storage, no swimming, running or gym use, and its audio is tuned for sleep content rather than for loud, dynamic music.
• Who PSIER is for: swimmers, runners, cyclists and anyone who wants music during activity while staying aware of their surroundings.
• Who LC-dolida is for: side sleepers, light sleepers, shift workers, travellers and anyone who wants quiet audio plus total darkness in bed.
The PSIER S18 is a sport headphone that happens to solve a problem almost nothing else solves: music underwater. The IPX8 rating means it can sit in up to two meters of water for an hour, and the sealed coating is built for it. What makes that actually work is the 32GB of internal memory. Bluetooth doesn't travel through water, so you load your own files — MP3, WMA, FLAC, APE or WAV — onto the headphones by connecting the magnetic charging cable to a computer, then double-click the power button to jump into MP3 mode. Up to 4,000 songs, no phone required, no signal to lose.
Away from water it behaves like a normal open-ear headphone. Bluetooth 6.0 with low latency, the ability to pair two or more devices and switch between them, a built-in microphone for calls, and 14mm bone conduction drivers covering 20Hz to 20,000Hz. The open-ear fit is the point: nothing blocks your ear canal, so you hear cars, other runners and announcements. Soft silicone cushions sit at the front of the ear and an adjustable strap is included for different head sizes. Battery is 8 hours in Bluetooth mode with a full charge in about 1.5 hours, and the companion app adds AI music creation and EQ tweaking.
LC-dolida Sleep Headphones: Who It's For
The LC-dolida is a completely different product wearing a similar name. It's a sleep mask with Bluetooth headphones built into the edges, and the design decisions all point one direction: lying down. The speakers are slim and thickly padded along the mask edges rather than jammed into your ears, which is the whole reason side sleepers can use it. There's no "rock under your head" feeling and no cartilage pressure building up over a night.
The mask itself is a 3-in-1: full blackout shading, audio, and a memory foam body lined with cooling ice silk that wicks moisture and stays breathable in warm rooms. The 3D contoured eye cups are deep and spacious, so they sit away from your lashes and eyelids — relevant if you have dry or sensitive eyes — and the flexible nose bridge seals light without pinching. The eye cup pads are removable for cleaning, and the strap adjusts to fit 23.5" to 25" heads.
Audio-wise it runs Bluetooth 5.4 for stable pairing, with speakers tuned for sleep material: white noise, ASMR, meditation, soft voices. Sound leakage is minimal, which matters if someone is sleeping next to you. Playtime is 15+ hours on a charge, easily a full night and then some. It works with any Bluetooth device and the manufacturer lists 24/7 customer support. It also comes in purple as a solid pattern, packed at 10.47 x 4.72 x 1.85 inches and 9.59 ounces.
Who should buy it: side sleepers, light sleepers, people who need darkness and masking sound together, shift workers sleeping during the day, and frequent flyers or hotel guests. Who should skip it: swimmers, runners, gym users and anyone who wants punchy music at volume. There's no IP rating, no built-in storage, and the sound profile is deliberately gentle. It's a sleep tool, not a workout headphone.
Side-by-Side: Which Should You Choose?
• Best for running, cycling and outdoor workouts → PSIER. Open-ear bone conduction keeps you aware of traffic, and the adjustable strap keeps it stable.
• Best for falling asleep to audio → LC-dolida. Padded edge speakers, blackout eye cups and a shape designed for pillow contact.
• Best for side sleepers → LC-dolida. That's the specific problem its ergonomics are built around.
• Best for battery life → LC-dolida. 15+ hours versus 8 hours on the PSIER, though the PSIER charges in about 1.5 to 2 hours.
• Best for phone-free listening → PSIER. 32GB of internal storage holds roughly 4,000 songs; the LC-dolida has none.
• Best for blocking out light and noise → LC-dolida. Total blackout plus masking audio, versus an open-ear design that lets everything in by definition.
• Best for calls and multi-device switching → PSIER. Built-in microphone, Bluetooth 6.0, and pairing with two or more devices.
In my opinion, if your listening happens while moving — swimming laps, running, riding — buy the PSIER Bone Conduction Headphones. The IPX8 rating and 32GB of onboard music are a genuinely rare combination, and no sleep mask can follow you into a pool. But if your listening happens in bed, the LC-dolida is the one I'd pick, because a bone conduction headphone pressed into a pillow is the wrong tool and a blackout mask with soft edge speakers is the right one. If you do both — swim by day, sleep with audio by night — these two aren't redundant. They're a pair.
how to make headphones music louder
Check the source first: raise the volume on the phone or player itself, not just the headphone, and confirm any in-app volume limiter is off. The PSIER also supports EQ adjustment through its companion app, which lets you shape the sound rather than only raise it. On the LC-dolida, the speakers are tuned for soft sleep audio, so it is not designed to get loud.
how to fix stereo headphones
Confirm the audio is actually in stereo at the source and that the cable or pairing is fully seated — a loose connection is the usual cause of one-sided sound. On the PSIER, if downloaded music won't play in MP3 mode, check the file is MP3, WMA, FLAC, APE or WAV, confirm the computer recognized the headphones, and re-copy the songs. A factory reset (hold the power button 10 seconds) also clears stuck modes.
how to test stereo headphones
Play a track you know has clear left-right separation and listen for each channel in turn; a mono mix will sound identical on both sides. For the PSIER, you can test in both modes — Bluetooth and MP3 — since a fault in one doesn't prove a fault in the other. If MP3 mode won't engage at all, make sure songs are loaded first, then try the reset.
how to make stereo headphones
You don't build stereo into a headphone — you feed it a stereo source. Both of these are wireless units, so the stereo image depends on the file or stream you send them. The PSIER's 32GB of storage plays whatever stereo files you copy onto it, while the LC-dolida relies entirely on a Bluetooth connection from your device.
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See also: IXTECH Mic Arm Boom vs Wigfar Bone Conduction Headphones, EMAIKER One Ear vs Callez Computer Headset, ProCase Noise Cancelling Headphones vs Floriogra Noise Cancelling Head, Voarmaks 4 vs Zosvoses ATH-M50X