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4157  Ear Simulator/Artificial Ear (IEC 60711 coupler with microphone and preamplifier)

The Ear Simulator consists of a main housing into which are assembled a number of rings whose shapes form annular air volumes connected to the main volume of the housing by air passages. The main ear canal volume is of a similar shape and volume to that of the actual human ear and provides a similar acoustic impedance to the insert earphone being tested. A 1/2-inch microphone is mounted in the housing of the Ear Simulator, terminating the main ear canal volume. Preamplifier Type 2669 is supplied with the set.
  Product Data

Uses

  • Frequency response, sensitivity and distortion measurements on insert earphones, e.g. used in hearing aids, operator headsets, etc.
  • Servicing of hearing aids
  • Production testing of earphones

Features

  • Conforms to IEC 60711-1981, ANSI S3.25-1979(R 1986) and ITU-T Rec.P 57 (Type 2)
  • Simple and straightforward calibration procedure
  • Well defined measuring conditions
  • Individually calibrated
  • Wide range of accessories included

To ensure that measurements are reproducible, a reference measurement plane is defined, see Fig. 1. This is perpendicular to the ear canal axis at the normal position of the tip of the ear mould.

Type 4157 is delivered in a mahogany case with an individual calibration chart giving all parameters for its correct use (see Fig. 3).

The Ear Mould Simulator DB 2015 is for testing button-type insert earphones. The External Ear Simulator DB 2012 simulates the whole of the external ear canal, and may be used to calibrate the measuring chain with the Pistonphone Type 4228. When used for this purpose the calibration level produced by the pistonphone is 0.7 dB lower than when calibrating a microphone because of the much larger volume of the Ear Simulator cavity. The Ear Mould Simulator DP 0370 is for testing behind-the-ear hearing aids. For testing ITE (in the ear) hearing aids, Adaptor DP 0530 may be used. The Ear Mould Holder DS 0540 is used to mount small ear moulds and CIC (completely in the canal) hearing aids on the Ear Simulator. DS 0541 is similar to DS 0540 but for larger moulds. The Tube Stud DP 0368 is for modular hearing aids.

Adaptor DP 0276 accepts a 1/4 inch microphone to be used as a sound source for testing the Ear Simulator. The adaptors are secured by an internally threaded collar DP 0286.

For customers already possessing a Preamplifier Type 2639, 2642 or a 2669, the Ear Simulator can be delivered without the Preamplifier Type 2669.



For a full Description and Specifications, see Product Data
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