Acoustic Design
Acoustic Design describes whether the headphone enclosure is open, closed or partly open to the surrounding air.
Open-back headphones allow sound to pass through the back of the enclosure. Closed-back designs enclose that side more fully; semi-open designs combine features of both. This describes the enclosure, separately from how the headphone is worn or how its driver produces sound.
Acoustic Design — Headphone
Open designs usually let more outside sound reach the listener and more reproduced sound escape to people nearby. Closed designs can reduce that exchange, but their isolation depends on construction and fit; closed-back does not mean silent outside or soundproof.
Choose the arrangement for the listening environment, including whether leakage would disturb someone or reach a recording microphone. This label does not establish bass extension, spatial presentation or sound quality. Active noise cancellation is a separate feature, and a closed enclosure does not prove that it is included.