In-ear, on-ear, over-ear: what the shape actually decides

The shape is about the seal, not the sound

A shop will tell you that one sort goes in your ear, one sits on it and one goes round it. True, and useless: it describes the box rather than what you will live with.

What the shape really decides is the seal. Seal the ear and the room stays outside while your music stays inside. Leave a gap and both travel through it. Almost everything you will notice — on a train, at a shared desk, late at night in a flat with thin walls — follows from that one thing.

There is a trap inside the over-ear family. Closed models behave as described above. Open-backed ones leak deliberately: the open back is where their spacious sound comes from. They are built for a quiet room you have to yourself, and no review score makes them right for a commute.

Where each one wins

• A sealed in-ear beats its size and its price. The seal does work that no amount of electronics can replace, which is why a modest sealed pair will outperform a pricier on-ear on a noisy train.
• On-ears leak the most of the three. Take a call on a quiet carriage and the carriage takes it with you.
• Over-ears carry their weight on the side of your head rather than on the ear itself, so they tend to win anything longer than an hour — and they run warm, which in August is not nothing.
• Glasses break the seal of an over-ear cushion. The gap looks trivial and costs more isolation than you would guess.
• Size never changes: in-ears live in a pocket, over-ears need roughly the room of a small lunchbox.

The right shape is the one that suits the place you will actually use them — which is rarely the shop.

Noise cancelling is a different thing from isolation

The two get sold as one, and the confusion is expensive.

Isolation is physical: material in the way of the sound. Cancelling is electronic: microphones hear the outside world and the headphone plays its opposite. They are good at different noises.

• Cancelling handles steady low sound very well — engines, fans, air conditioning, the rumble of a carriage.
• It is far weaker against speech and sudden sharp noises, which is precisely what distracts you in an office or a café.
• It cannot stand in for a seal. If an in-ear tip does not fit your ear, no circuit will rescue it — and a badly fitting tip is the usual reason a pair is described as sounding thin.

Before you pay extra for cancelling, name the noise you want gone. If it is people talking, a proper seal will do more than an expensive circuit.

The figures printed on the box

• Driver size in millimetres. It tells you how much room the designer had, not how good the result is, and it cannot be compared across shapes.
• Frequency response, almost always 20 Hz to 20 kHz. It appears on the best and the worst boxes alike. Without a tolerance it means nothing.
• Battery hours. Measured with cancelling switched off and at a modest volume — not the way you will use them.
• Codec names and hi-res badges. They count for far less than fit. A flawless codec leaking out of a bad seal is the worse of the two problems.

And then there is the price

Headphones are where crossed-out prices are least reliable: models are replaced constantly, and an old recommended price stays in the listing long after anyone paid it.

• Ask what the reduction is measured against. A crossed-out price only means something if the shop charged it before. Against a manufacturer’s recommended price that nobody has paid for two years, a percentage means nothing at all.
• Use the reference the shop itself shows. On Amazon.co.uk that is often a was price, worked out from what the item recently sold for rather than from a list price. It is much harder to inflate, and it is the one we quote when we publish.
• Check the exact model code rather than the family name. A successful name gets carried across revisions that do not sound alike, and the pair on offer is often the older one — fine, if you are paying older-revision money.
• Read the condition. Renewed and open-box listings are common in this category and can be a real bargain, but they are not new, and the discount ought to reflect that and not just the list price.

This is the check we run before anything goes out. If a price does not survive it, the deal does not get published — which is why some days we publish less.