If you want wired in-ear listening with a snug fit and included tip choices, choose Sennheiser CX 300S; if you need wireless over-ear convenience and long battery life, choose Sony WH-CH520. For kids, the decision comes down to whether a simple wired earbud setup or a rechargeable Bluetooth headset makes more sense for their routine.
The CX 300S offers four ear-adapter sizes, an inline button for music and calls, and an in-ear design intended to reduce ambient noise. The WH-CH520 trades the earbud fit and cable for Bluetooth, an adjustable on-ear design, and up to 50 hours of battery life.
• Sennheiser CX 300S: Its in-ear fit, four included tip sizes, and inline control suit focused listening; the trade-off is a wired connection and the need to find a comfortable tip fit.
• Sony WH-CH520: Bluetooth, multipoint pairing, and up to 50 hours of battery life make it convenient for longer stretches; the trade-off is that it needs charging and rests on the ears rather than inside them.
• For calls and quick controls: The CX 300S has a one-button inline remote, while the Sony has a built-in microphone and wireless controls.
• For listening away from a charger: The Sony’s stated battery life is up to 50 hours; the Sennheiser does not need charging but must stay connected by its cable.
• Choose Sennheiser if you want wired in-ear headphones with several fit options; choose Sony if wireless freedom and a rechargeable, adjustable headset matter more.
The CX 300S is a wired in-ear model with a 3.5 mm plug, a dynamic driver, and an 18-ohm impedance. Its defining practical advantage is the fit kit: four silicone ear-adapter sizes, from XS through L, let the listener try different options rather than make do with one fixed tip size. That matters especially for a child, since a tip that fits well can feel more secure and help the in-ear design reduce surrounding sound.
Sennheiser describes the sound as detailed, balanced, and enhanced in the bass. The listed frequency range is 17 Hz to 21,000 Hz. Those figures identify the product’s stated audio range, but they do not guarantee that every listener will hear the same result. The design is aimed at someone who wants compact, straightforward listening rather than Bluetooth features. There is no battery to recharge, and the one-button inline remote can play or pause music and handle calls without reaching for the connected device.
How We Research
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-19 · 8 min read · Independent comparison
Who should skip it: Skip the CX 300S if you want Bluetooth, a headband, or a cable-free setup.
The WH-CH520 is a wireless, on-ear headphone with Bluetooth 5.2, a built-in microphone, and multipoint connection. Multipoint lets it connect to two Bluetooth devices at once, which can be useful when a listener moves between a laptop and phone. A child doing schoolwork on one device and listening to something on another may appreciate not having to treat each device switch as a fresh pairing task.
Sony states up to 50 hours of battery life, with quick charging that can provide up to 90 minutes of playback after three minutes of charging. The supplied USB Type-C cable is for charging. This makes the WH-CH520 a practical choice for a family that prefers wireless listening and does not want to recharge after every short session. The battery still requires attention eventually, so it is not the same as a wired model that draws power from its connected device.
The adjustable headband, soft ear pads, head cushion, lightweight construction, and swivel earcups all point toward a headset that can be put on, adjusted, and taken off without inserting tips into the ear canal. Sony also offers EQ customization through its Headphones Connect app and DSEE processing for compressed music files. Those features give listeners some ways to tailor playback, though they add a different kind of setup than the CX 300S’s plug-and-listen approach. The built-in microphone supports hands-free calls, and voice-assistant access is also listed.
Who should skip it: Skip the WH-CH520 if you specifically want wired in-ear headphones or do not want to keep a rechargeable battery charged.
• Best for wired listening → Sennheiser CX 300S. Its 3.5 mm connection suits someone who wants a cable and does not want to manage headphone battery life.
• Best for wireless listening → Sony WH-CH520. Bluetooth 5.2 removes the headphone cable from the listening setup.
• Best for extended time between charges → Sony WH-CH520. Its stated battery life is up to 50 hours, and quick charging is listed as an option for a short top-up.
• Best for choosing an earbud fit → Sennheiser CX 300S. Four included adapter sizes give the listener several tip options, an important consideration for smaller or differently shaped ears.
• Best for switching between two devices → Sony WH-CH520. Multipoint supports simultaneous connection to two Bluetooth devices.
• Best for simple inline control → Sennheiser CX 300S. Its one-button remote handles play, pause, and calls on the connected device.
• Best for an adjustable on-ear style → Sony WH-CH520. It has an adjustable headband, soft ear pads, and swivel earcups rather than removable in-ear tips.
• Best for sound customization → Sony WH-CH520. The app’s EQ Custom feature allows music preferences to be adjusted, while DSEE is intended to improve the playback of compressed music files.
I would choose the Sony WH-CH520 for most kids who want wireless headphones for music, videos, and calls. The adjustable on-ear design avoids the need to select an ear-tip size, while multipoint and up to 50 hours of stated battery life add useful everyday flexibility. For kids, I would still make sure the on-ear fit feels comfortable before settling on it.
I’d choose the Sennheiser CX 300S instead when wired in-ear listening is the priority and its four tip sizes are a real advantage. It is a more focused choice, not a substitute for wireless convenience. If I were buying with a child’s routine in mind, I’d start with how they prefer headphones to sit and whether managing a cable or a battery is the easier trade-off at home.
First, consider fit rather than assuming one style will suit every child. The Sennheiser uses silicone ear adapters in four sizes, and its fit affects both comfort and the intended reduction of ambient noise. The Sony rests on the ears, with an adjustable headband and soft ear pads. These are different wearing experiences, so a child’s comfort preference may settle the decision faster than a feature list.
Next, think about the listening setup. The CX 300S uses a 3.5 mm jack and a cable; the Sony connects wirelessly over Bluetooth and has no headphone jack. Check which connection fits the devices the child will use. The Sony’s wireless convenience comes with a charging routine, while the wired Sennheiser avoids that task but keeps the listener tethered to the connected device.
For families considering the Sony for travel or longer listening stretches, its up-to-50-hour battery claim and quick-charge feature are useful details to weigh. For someone who shifts between a laptop and phone, multipoint is another clear advantage. The Sennheiser’s case is simpler: choose it for the in-ear form, included fit options, and inline play, pause, and call control.
Neither model is an ear clip headphone. If you are searching for the best wireless clip-on earbuds for kids, these two options do not match that particular design request: the Sony is an on-ear headset, and the Sennheiser is an in-ear wired earphone. Likewise, shoppers looking for long battery life Bluetooth earbuds for kids should note that the CX 300S is not Bluetooth, while the WH-CH520 is an on-ear headphone rather than an earbud.
For a child who wants wireless listening and an adjustable headband, the Sony is the more fitting option. The Sennheiser may suit a child who prefers in-ear headphones and can find a comfortable fit among its four included tip sizes.
No battery is listed for the CX 300S. It connects to a device through a 3.5 mm jack, so the headphone itself does not require charging, but the cable must remain connected during listening.
Sony specifies up to 50 hours of battery life. The headphones also support quick charging, with up to 90 minutes of playback from three minutes of charging; actual listening time can vary with use.
No. The Sennheiser CX 300S is a wired in-ear headphone, and the Sony WH-CH520 is a wireless on-ear headphone. Shoppers specifically seeking an ear clip design or wireless earbuds should look for a different style.
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