Bruel & Kjaer 4157 Ear Simulator IEC 60318-4
Overview
The Bruel & Kjaer 4157 is an ear simulator built to the IEC 60318-4 specification, providing a standardized acoustic coupler for testing hearing aids, earphones and audiometric equipment. The coupler simulates the acoustic load of the human ear so that measurements made on the bench match the behaviour of the device in real use. The 4157 is part of the Bruel & Kjaer range of acoustic simulators used by laboratories, hearing aid manufacturers and audiology clinics.
The IEC 60318-4 coupler family is the basis of audiometer calibration in most countries, and the 4157 is one of the recognized implementations of the standard. Laboratories use the simulator together with the B&K measurement chain to keep their calibration results traceable. Seven Star LLC supplies the 4157 with the documentation required for the laboratory records. The simulator is designed for sustained use in a laboratory environment, with the coupler body and microphone assembly protected by its storage case. The measurement chain is verified against the reference before each calibration series.
Engineering and Design
The ear simulator contains a precisely machined coupler cavity that reproduces the acoustic impedance presented by the human ear over the frequency range relevant to audiometry. A measurement microphone inside the coupler converts the sound pressure at the ear reference point into an electrical signal for the analysis system. The design follows the IEC 60318-4 standard, giving results that are comparable between laboratories and traceable to the standard.
For audiometer calibration, the earphone under test is coupled to the 4157 with the specified force and the sound pressure at the ear reference point is measured over the audiometric frequency range. The results are compared with the required levels and the audiometer output is adjusted to meet the standard. For hearing aid measurements, the coupler is used with the test box and the same microphone chain, keeping the whole measurement setup compliant with the relevant IEC standards.
For audiometer calibration, the earphone under test is coupled to the 4157 with the specified force and the sound pressure at the ear reference point is measured over the audiometric frequency range. The results are compared with the required levels and the audiometer output is adjusted to meet the standard. For hearing aid measurements, the coupler is used with the test box and the same microphone chain, keeping the whole setup compliant with the relevant IEC standards. The coupler is cleaned and inspected before each calibration session, and the measurement microphone is checked against the laboratory reference. The reference microphone of the laboratory is verified against the national calibration chain at the scheduled interval, and the 4157 is included in the laboratory equipment register. The ear simulator is supplied with the manufacturer documentation covering installation and the recommended test procedures for the coupler. The 4157 is used together with the standardized measurement procedures of the laboratory, and the results are reported with the coupler identification. The simulator is cleaned with the recommended procedure and inspected for damage at each audit interval.
Key Features
- IEC 60318-4 ear simulator for audiometry and telephone testing
- Standardized acoustic coupler cavity
- Measurement microphone at the ear reference point
- Suitable for hearing aid and earphone testing
- Used for audiometer calibration
- Part of the B&K acoustic simulator range
Applications
The 4157 is used in audiology clinics, hearing aid manufacturing and repair facilities, calibration laboratories and telecom testing centres. It supports audiometer calibration, hearing aid measurements and earphone testing in accordance with the IEC 60318-4 standard.
Specifications
| Product | Bruel & Kjaer 4157 ear simulator |
| Standard | IEC 60318-4 |
| Application | hearing aid, earphone and audiometer testing |
| Measurement | sound pressure at ear reference point |
| Coupler | standardized acoustic impedance simulation |
| Microphone | integrated measurement microphone |
Why Seven Star LLC
Seven Star LLC supplies Bruel & Kjaer acoustic simulators, microphones and measurement instruments to laboratories, clinics and industrial test facilities across Oman and the GCC. Every item is verified against the original B&K product number before your order is confirmed.
Technical Specifications
The Brüel & Kjær Type 4157 Ear Simulator is a precision acoustic coupler with a built-in 1/2-inch microphone and preamplifier, designed to simulate the acoustic impedance of the occluded human ear canal for testing insert earphones and hearing aids. Its effective volume is 1.26 ±0.03 cm³ at 500Hz, with a resonant frequency of 13.5 ±1.5kHz. The coupler housing measures 23mm in height with a maximum diameter of 23.77mm, and calibration is performed under reference conditions of 23 ±3°C and 101.3 ±3kPa. The instrument is rated for 5–40°C operation and -25°C to +70°C storage.
Standards and Applications
The Type 4157 complies with IEC 60711-1981, ANSI S3.25-1979 (R1986), and ITU-T Recommendation P.57 (Type 2), the international standards governing occluded-ear simulator design for hearing-device testing. Safety compliance is per EN 61010-1/IEC 1010-1, EMC per EN 50081-1/CISPR 22 (emission) and EN 50082-1 (immunity), and environmental testing per the IEC 68 series. It is used for insert-earphone frequency response, sensitivity, and distortion testing, hearing-aid servicing and calibration, and earphone production quality control — applications where a repeatable, standardized simulation of the human ear canal’s acoustic impedance is essential for meaningful, comparable measurements across different test benches and manufacturers.
Why Seven Star LLC
Seven Star LLC supplies genuine Brüel & Kjær acoustic test instrumentation, including the Type 4157 Ear Simulator, to hearing-device manufacturers, calibration laboratories, and audiology testing facilities across Oman and the wider GCC, and confirms the exact coupler configuration and calibration certificate requirements before confirming an order.
Request a Quote for Bruel & Kjaer 4157 Ear Simulator IEC 60318-4
Submit a formal inquiry through our RFQ page with the ear simulator product number 4157 and your measurement application. We will confirm availability and respond with a formal quotation. | Inquiry Form
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