If you want a close-fitting, noise-isolating wired earphone for kids, choose Sennheiser CX 300S; if you need lightweight, cushioned on-ear headphones for kids, choose Sony ZX Series. Both have a 3.5 mm wired connection and an inline remote with a microphone, but their fit and sound isolation are quite different. The right choice comes down to whether a child is more comfortable with earbuds or earcups.
Sennheiser CX 300S vs Sony ZX Series at a Glance
• Sony ZX Series strength: Cushioned on-ear pads and swiveling earcups offer a different, easy-to-store design; its trade-off is that the listed noise-control feature is none.
• Sennheiser CX 300S: A sensible pick for someone who wants a snug earbud fit, reduced ambient noise, and a simple music-and-call remote.
• Sony ZX Series: A better match for someone who prefers headphones resting on the ears, with a microphone and swiveling cups.
• Who each suits: Choose based on the wearer’s comfort preference first; neither model is wireless, and both connect through a 3.5 mm jack.
The CX 300S is a wired, in-ear model with rounded tips and four included silicone ear-adapter sizes: XS, S, M, and L. That range gives the wearer a chance to find a more secure, comfortable fit instead of relying on a single tip size. Fit matters here. The product information notes that tips that do not suit the ear canal, or earbuds that are not worn properly, can affect sound and call performance. For a child, an adult should help choose the appropriate tip and check that each earbud sits comfortably.
Its in-ear design is intended to reduce ambient noise, which may suit listening in a busy room or during a commute. The CX 300S also has a one-button inline remote for playing or pausing music and taking calls without reaching for the connected device. It is wired through a 3.5 mm jack, so it is not a wireless option; the device being used needs a compatible jack or connection.
Sennheiser describes the sound as detailed, balanced, and supported by enhanced bass. The listed frequency range is 17 Hz to 21,000 Hz, and the transducers have an 18-ohm impedance. Those figures identify the product’s stated audio range and impedance; they do not guarantee that every listener will hear the same result. The practical appeal is a compact earbud format with a remote and a fit-adjustment option.
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-19 · 7 min read · Independent comparison
Who should skip this: Skip the CX 300S if the wearer dislikes in-ear tips or specifically wants a headband-style pair of headphones.
Sony ZX Series: Who It's For
The Sony ZX Series is a wired, on-ear headphone with cushioned earpads and a closed-back design. Instead of sitting inside the ear, its cups rest on the ears. That distinction can make it a more comfortable format for someone who does not want silicone ear tips. The cushions and closed-back construction are part of the design, but Sony lists its noise control as none. Buyers looking for a stated noise-isolation feature should keep that difference in mind.
The earcups swivel for storage and portability, and the listed driver size is 30 mm. Sony describes the sound as full and balanced, with a frequency range stated as 12 Hz to 22,000 Hz in its product description. The product information also lists a frequency range of 5–22 kHz, so the sheet provides two different lower-end figures. Neither range alone establishes how the headphones will sound to an individual listener.
The ZX Series has an inline remote and built-in microphone for hands-free calls with selected smartphones. It connects through a 3.5 mm L-shaped stereo mini plug, so it is wired rather than Bluetooth. The product description specifies a 1.2 m Y-type cable. For everyday use, that means the listening device remains connected by a cord, while the swiveling cups can make the headphones easier to put away when they are not being worn.
Who should skip this: Skip the Sony if the wearer wants earbuds that sit inside the ear or needs a model with listed noise control.
• Prefer earbuds over earcups → Sennheiser CX 300S. Its rounded in-ear tips sit inside the ears, with four sizes supplied to adjust the fit.
• Prefer cushioned pads over silicone tips → Sony ZX Series. Its earpads rest on the ears rather than entering the ear canal.
• Want a design intended to reduce ambient noise → Sennheiser CX 300S. Its in-ear design is specified to reduce outside sound; the Sony’s noise-control listing is none.
• Want swiveling earcups for storage → Sony ZX Series. The cups swivel to support storage and portability, a feature the Sennheiser does not list.
• Need a corded microphone and remote → Either model may fit. Both have an inline remote and microphone, though Sony specifies hands-free calls with selected smartphones.
• Need a 3.5 mm wired connection → Either model. Both use a 3.5 mm jack, so check that the intended device has a compatible connection.
• Want several fit options in the box → Sennheiser CX 300S. The four ear-adapter sizes are a concrete advantage when one tip size is not comfortable.
• Want on-ear headphones with a 30 mm driver → Sony ZX Series. Its listed driver size and cushioned earcups make it the clearer choice for that form factor.
Buying Considerations
For kids, start with fit and comfort rather than choosing by a frequency-range figure. An in-ear headphone for kids can be a good match if the child is comfortable with ear tips and can find a secure fit. The CX 300S includes four sizes, but a poor fit can affect sound and call performance. That makes trying the available tips carefully an important part of choosing it.
Neither product is Bluetooth. If the search is specifically for bluetooth headband headphones for kids, neither of these models meets that requirement: both are wired and use a 3.5 mm jack. Check the child’s device before choosing, especially if it does not have a compatible headphone jack.
Both include call controls, but neither sheet provides evidence that one is the best crystal clear calls headphones for kids. Sennheiser notes that a suitable ear-tip fit can affect call performance; Sony specifies a microphone for hands-free calls with selected smartphones. If calls are a priority, confirm that the intended phone supports the remote and microphone functions.
In my opinion, I would choose the Sennheiser CX 300S for kids who are comfortable wearing earbuds. Its four tip sizes and stated ambient-noise reduction give it a useful combination for focused listening, while the inline remote handles basic music controls and calls. I would choose the Sony instead for a child who clearly prefers cushioned on-ear headphones and swiveling earcups. My recommendation is the CX 300S only when its in-ear fit suits the wearer; comfort should decide the final call.
Neither is automatically the better fit for every child. The Sennheiser is an in-ear model with four tip sizes, while the Sony rests on the ears with cushioned pads. Choose the form the child finds comfortable.
No. Both are wired and use a 3.5 mm jack. They are not Bluetooth headband headphones, so check device compatibility before choosing either one.
The CX 300S has an in-ear design intended to reduce ambient noise. Sony lists no noise control for the ZX Series, though it describes its closed-back design as sealing in sound. Neither product sheet identifies active noise cancellation.
Both have an inline remote and microphone. Sennheiser says the one-button remote can take calls, while Sony specifies hands-free calls with selected smartphones. The CX 300S product information also notes that fit can affect call performance.
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