Headphones and Earbuds: The Specifications That Actually Matter

Audio is a category where the numbers on the box correlate weakly with how something sounds. A few specifications do matter, mostly the ones concerning fit, connection and power rather than the ones about frequency.

Specifications that mean something

• Fit and seal. Not a number, and the single biggest factor in how in-ear headphones sound. A poor seal removes bass entirely. Multiple tip sizes in the box is a meaningful feature.
• Bluetooth codec support. Determines the quality of the wireless link — but both the headphones and your phone must support the same one. Checking your phone first saves paying for a codec you cannot use.
• Battery life, and whether it is quoted with noise cancelling on. The headline figure is usually the best case with features off.
• Charging type and quick-charge. USB-C is now standard; a short charge giving a usable amount of playback is genuinely useful.
• Impedance, for wired headphones. High-impedance models need more power than a phone provides and will sound quiet and thin without an amplifier.
• Weight and clamping force, for over-ear models worn for hours.

Specifications that mostly do not

• Frequency response range. Quoted as a very wide range on almost everything. It says nothing about how the range is balanced, which is what you actually hear.
• Driver size in millimetres. Bigger is not better; tuning matters more than diameter.
• "Hi-Res" badges. A certification about capability, not about quality of tuning, and wireless listening often does not deliver it anyway.
• Number of drivers in an earbud. More drivers is a design choice, not a quality tier.

Noise cancelling, honestly

Active noise cancelling works best on constant low-frequency sound — engine noise, air conditioning, a train. It works far less well on speech and sudden sounds, which is what most people are actually trying to block in an office. If your problem is a talkative room, passive isolation from a good seal may do more than any electronic system.

Transparency modes vary widely in how natural they sound, and this is not something a specification will tell you. It is worth reading reviews specifically for that feature if you will use it.

Wired, wireless, or both

Wireless is the default and the convenience is real. The costs are a battery that ages, a connection that occasionally drops, and a device that eventually becomes unusable when the battery no longer holds charge. Wired headphones have none of those failure modes and no battery to replace, which is why they remain the better long-term value if the cable is not a problem for you.

If you buy wireless, treat it as a consumable with a life measured in years rather than a permanent purchase, and price it accordingly.

Fit matters more for earbuds than anything else

Earbuds that do not stay in are unusable regardless of how they sound. Ear shape varies and no review can tell you about yours. Where a retailer has a generous return policy on opened earbuds, that policy is worth more than a small price difference.

Before you order

Check whether the retailer accepts returns on opened audio products, since hygiene rules often make earbuds non-returnable and that varies by seller. Check what tips and cables are included. Check the codec your phone supports before paying extra for one it does not. And for wired models, check the connector type against the device you will actually plug them into.