BS EN 60118-8:2005 – Electroacoustics — Hearing aids — Part 8: Methods of measurement of performance characteristics of hearing aids under simulated in situ working conditions

3.1 sound pressure level throughout this standard all sound pressure levels (abbreviated SPL) are referred to 20 μPa
3.2 pinna simulator device which has the approximate shape and dimensions of a median adult human pinna
3.3 ear simulator device for measuring the output sound pressure level of an earphone under well defined loading conditions in a specified frequency range. It consists essentially of a principal cavity, acoustic load networks and a calibrated microphone. The location of the microphone is chosen so that the sound pressure at the microphone corresponds approximately to the sound pressure existing at the human eardrum
3.4 occluded-ear simulator ear simulator which simulates the inner part of the ear canal, from the tip of an ear insert to the eardrum
3.5 ear canal extension device which connects the concha portion of the pinna simulator with the outer (reference plane) face of the occluded-ear simulator, simulating the outer part of the ear canal excluding the pinna
3.6 ear insert simulator device used to represent the acoustic coupling between an earphone and the ear canal (e.g. an earmould or a similar device without a connecting tube)
3.7 manikin (head and torso simulator) head and torso simulator extending downward from the top of the head to the waist and designed to simulate the acoustic diffraction produced by a median adult human head and torso. The head includes two pinna simulators, and contains at least one occluded-ear simulator
3.8 reference point of a subject or manikin point bisecting the line joining the centres of the openings of the ear canals (at the junction between concha and ear canal) (see Figure C.1 )
3.9 plane of symmetry of the manikin plane passing through the reference point of the manikin that divides the left and right portions of the manikin into symmetrical halves (see Figure C.1 )
3.1 0 axis of rotation of the manikin straight line passing through the reference point of the manikin and lying in the plane of symmetry of the manikin, and having a direction that would be vertical if the manikin were mounted in a position corresponding to that of a standing person (and about which the manikin can be rotated) (see Figure C.1 )
BS EN 60118-8:2005 – Electroacoustics — Hearing aids — Part 8: Methods of measurement of performance characteristics of hearing aids under simulated in situ working conditions