Bruel and Kjaer
It is intended for dimensions on earphones attached to the ear through ear inserts, for example, tubes or eartips or ear moulds. The 4157 Ear Simulator model intimately imitates the acoustical features of the human ear, putting the insert earphone forward under examination through impedance resembling that of a genuine human ear. Applications include: Frequency response, density and distortion dimensions on insert earphones, such as, use in operator headsets, hearing aids, etc., hearing aids repairing and service checking of earphones. Characteristics include: Matches ANSI 3.25 (2009), IEC 60318-4 (2010) and ITU-T Rec. P.57 category-2, precise calculating conditions, easy and simple adjusting procedure, extensive array of accessories incorporated and individually tuned.