Explainers
Open-back or closed-back headphones: what openness changes in the sound
Behind every driver there is an earcup. Whether it is solid or perforated changes the soundstage, the behaviour of the bass, the isolation and what your neighbours hear. It is one of the most fundamental choices in hi-fi and in the studio.
A question of the rear wave
A driver's diaphragm pushes air towards the ear but also, in the opposite direction, backwards. What should be done with this rear wave? The whole difference between open-back and closed-back headphones lies in the answer.
In closed-back headphones, the earcup is sealed. The rear wave stays trapped, reflects off the walls and partly returns to the diaphragm. In open-back headphones, the earcup is replaced by a grille: the rear wave escapes freely into the room.
What openness brings
With no internal reflections, the diaphragm works under simpler conditions. Three effects can be heard.
- A wider soundstage. The sound no longer seems shut in between your ears. Instruments appear to be placed around your head, with air between them. It is a subjective impression, but a consistent one from listener to listener.
- A more natural timbre. The earcup resonances that colour the mids of many closed-back headphones disappear. Voices and acoustic instruments benefit.
- Greater comfort. Air circulates: less heat, no closed-in feeling around the ears, and you hear your own voice normally.
What it costs
- No isolation. You hear the room as if you were wearing nothing. A dishwasher is enough to spoil your listening.
- Substantial leakage. Open-back headphones behave like two small loudspeakers: at normal volume, someone next to you can follow your music. Out of the question at the office, on public transport or near a microphone.
- Recessed sub-bass on most dynamic-driver models. With no enclosed volume to maintain the pressure, the level falls away below about 50 Hz. Open-back planar headphones largely escape this rule (see driver types).
The strengths of closed-back headphones
Closed-back headphones are the all-round tool. Their earcups attenuate outside noise by 10 to 25 decibels in the mids and treble, and keep your music to yourself. The pressure of the trapped air supports the deep bass, which is often more physical than on an open-back model.
Their difficulty lies in controlling internal reflections. Good models manage it with absorbent materials and angled or damped earcups; bad ones sound “hollow” or “boxy”. Good closed-back headphones do not sound closed in, but they generally cost more to design than open-back headphones of the same standard.
They are also the only possible basis for active noise cancelling: to cancel noise, you first have to control what gets into the earcup.
Side by side
| Open-back | Closed-back | |
|---|---|---|
| Soundstage | Wide, airy | More intimate |
| Isolation from outside noise | None | Good |
| Leakage to the outside | Heavy | Low |
| Deep bass | Recessed (except planars) | Present, punchy |
| Heat | Low | More noticeable |
| Uses | Hi-fi, mixing, gaming in a quiet room | Recording, office, commuting |
What about semi-open?
Some headphones are described as semi-open: their earcups have calibrated vents rather than a full grille. The aim is to keep some of the bass pressure while limiting resonances. In practice, they leak and let noise in almost as much as an open-back model: treat them as such when choosing where to listen.
Which to choose for each use
- Attentive listening at home: open-back, if the room is quiet and you are alone. This is where the design gives its best. See audiophile headphones.
- Mixing and mastering: open-back, to judge spatial placement and balance without earcup colouration.
- Recording: closed-back, without exception. Open-back headphones leak into the mic, and the click track ends up on the vocal take. See studio headphones.
- Gaming: open-back for positional accuracy in a quiet room, closed-back if you play next to someone or with a sensitive mic.
- Office, commuting, travel: closed-back, with no alternative.
Worth knowing. Many benchmark open-back headphones have a high impedance and were designed to be plugged into an amplifier. Before you buy, read impedance, sensitivity and amplification.
Sources and references
- IEC 60268-7 — Sound system equipment: headphones and earphones
- Olive, Welti, Khonsaripour — A Statistical Model that Predicts Listeners' Preference Ratings of Around-Ear and On-Ear Headphones, Audio Engineering Society Convention 144, 2018
Frequently Asked Questions
Can you use open-back headphones on public transport?
No. Open-back headphones do not block outside noise, which forces you to turn the volume up to a level that is dangerous for your hearing, and they leak sound to those around you. On public transport, you need closed-back headphones or in-ears.
Do open-back headphones have less bass?
They generally have less sub-bass, below about 50 Hz, when they use a dynamic driver. The bass is still there, and often more precise than on closed-back headphones. Open-back headphones with planar drivers, on the other hand, reach very low with no roll-off.
Are open-back headphones better for your hearing?
Not in themselves. They get less warm and are less tiring over long sessions, but the risk to hearing depends solely on volume and listening time. In a noisy place, open-back headphones actually push you to listen louder.