Dynamic headphones are the most common type of headphone, so let's take a closer look at the three basic earpiece designs.
Supra-aural headphones, also known as on-ear, open-back or open-air headphones, sit lightly on or over the ear. The ear cups are generally softly padded and rotate freely to enhance fit and reduce pressure points. Because they sit on the ear, on-ear headphones leak sound into the external environment and allow ambient noise in.
Circumaural headphones, also known as around-ear or closed-back headphones, completely enclose the listener's ears. Because they form an airtight seal, they block out external noise without leaking sound to the outside. This improves sound quality, but circumaural headphones tend to be heavier and less comfortable.
In-ear headphones come in two styles: ear buds and canal headphones. Ear buds are worn in the opening of the ear, while canal headphones are seated in the canal itself, forming an airtight seal. Sound quality tends to be excellent with in-ear headphones, although this is dependent on how well they fit in the listener's ear. For this reason, canal headphones, which fit tightly in the ear like earplugs, are often preferred by musicians or others wanting superior sound quality.
We'll look at exactly how noise-canceling headphones manage to "cancel" noise next.