Headphones 74325.4.3 Intra-Aural
Another category that has been recently commercialized is the intra-aural type, which
actually fi ts into the ear to provide very lightweight personal listening ( Figure 25.8 ).
Obviously the transducer size limits the bass performance, although this is helped by
channeling the sound almost directly into the ear canal.
25.5 Measuring Headphones .........................................................................................
Both types of headphone work into an entirely artifi cial environment in which the close
proximity of the diaphragm and, in the case of the closed headphone, a trapped volume of
Figure 25.7 : Supra-aural headphones (RE 2390) from Ross Electronics.