GRAS 45BB-7 Head & Torso for Test of Binaural Hearing Aid, 2-Ch LEMO

Introduction

The KEMAR head and torso simulator was introduced by Knowles in 1972 and quickly became the industry standard for hearing-aid manufacturers and research audiologists (visit KEMAR.us to read the full story). It is based on worldwide average human male and female head and torso dimensions. It meets the requirements of ANSI S3.36/ASA58-2012 and IEC 60318-7:2011.

The current KEMAR Head and Torso has the same dimensions and acoustical properties as the original KEMAR, but has been developed further by GRAS to meet the industry’s demand for realistic measurements of hearing aids, headphones, and headsets. It provides acoustic diffraction similar to that encountered around the median human head and torso, both in the proximity and in the far-field.

As all the preconfigured 45BB KEMARs consist of the same basic 45BB KEMAR Non-configured, plus a set of application-specific accessories, the full information about a given KEMAR configuration is obtained by combining the information about the 45BB KEMAR Non-configured and the information for a given configured version as found in the present text. Read about the non-configured KEMAR here.

Design

The 45BB-7 is a KEMAR head and torso for binaural hearing aid test, with externally polarized ear simulators and large 55 Shore OO pinnae. A special feature is that the ear holder plates, ear canal extensions and accompanying screws are made of POM, Nylon, and Teflon to allow RF signals to pass inside KEMAR’s head.

It is delivered fully configured, individually calibrated and ready for use. In addition to a system calibration certificate, a USB flash memory with simulation data is included.

Apart from the abovementioned use of plastic materials, the main configuration specific components of the 45BB-7 are the GRAS RA0045 Ear Simulator According to 60318-4 and the KB0066/KB50065 large pinnae.

The 60318-4 Ear Simulator

The acoustic input impedance of the RA0045 Ear Simulator closely resembles that of the human ear and, as a result, loads a sound source in very much the same way.

It complies with IEC 60318-4 and is measured and calibrated according to ITU-T P.57. It embodies a number of carefully designed volumes connected via well-defined and precisely tuned resistive grooves. In an equivalent electrical circuit, capacitors would represent the volumes, and inductance and resistance would represent respectively air mass and air flow within the resistive groves.

Read more about RA0045 here.

The KB0065/KB0066 Pinna

The KB0065 and KB0066 are large straight pinnae for use with a straight ear canal extension. The hardness is 55 Shore 00. They comply with the IEC and ITU-T recommendations.

Other accessories for this configuration are listed in the Ordering Info tab.

Performance and warranty

KEMAR is made of components from our standard portfolio, all manufactured of high-quality material and branded parts that were chosen and processed to ensure life-long stability and robustness. This enables us to offer 2 years warranty against defective materials and workmanship.
Exceptions: Microphones included in KEMAR as for these our normal 5-year warranty apply. The warranty period for cables is 6 months.