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Range of Products

We design and manufacture an extensive range of products to cover virtually all front-end equipment needed for the precise and reliable measurement and recording of acoustic signals; from the transducer to the input of an A/D converter.

These are complemented by a range of more specialised transducers and accessories for more specific applications.

picture gallery



Recent Additions

½" Low-noise Microphone System Type 40HL

The G.R.A.S. ½″ Low-noise Microphone System Type 40HL measures sound pressure levels well below the threshold of human hearing. It is thus generally suitable for sound-power measurements on even very quiet products. Its very wide dynamic range permits measurements down to below 6,5 dBA re. 20 μPa (in 1/3-octave bands) from 20 Hz to 20 kHz.

Pistonphone Type 42AP

Handset Positioning System Type 45EA

For testing mobile and cordles phones, the Handset Positioning System Type 45EA positions handsets onto KEMAR Manikin Type 45BM.

The positioning system features nine moving segments allowing handsets to be exactly positioned according to requirements/standards. For repeated measurements, all moving segments are provided with graduated scales to be read off. 
The handset fixture with a spring arrangement provides for easy attachment/detachment of practically any mobile/cordless handset. It is applicable for both right and left ear, and it is easy to retrofit. 

Click on the picture for more info.

Pistonphone Type 42AP

KEMAR Manikin with Mouth Simulator Type 45BM

The KEMAR ® Manikin Type 45BM is an acoustic research tool with built-in mouth and ear simulators. The manikin simulates the changes that occur to sound waves as they pass a human head and torso, such as the diffraction and reflection caused by each ear.
The mouth simulator is a sound source that simulates the sound field at close quarters and is typically used for testing handsets (e.g. mobile phones) by aid of the Handset Positioning System Type 45EA.
The artificial ear consists of three parts:
The inner ear, the IEC 60711 Ear Simulator
The middle ear, a well-defined and standardized ear-canal extension made of steel.
The outer ear, the KEMAR Pinna; several types are available (options for both hardness and size).

Click on the picture for more info.

Pistonphone Type 42AP

Microphone Calibration System Type 90CA

The G.R.A.S. Microphone Calibration System Type 90CA provides for automated and reliable level and frequency response calibration of measurement microphones. The implemented calibrations methods conform with relevant standards.

Click on the picture for more info.
Microphone Calibration System Type 90CA

CCP Intensity Probe Type 50GI

Type 50GI is a sound intensity probe for direct connection to signal analyzers or data acqusition devices with IEPE inputs. The probe includes a pair of phase-matched prepolarized precision microphones which meet the requirements in IEC standard 61043* for a class-1 intensity probe. The small rugged ¼″ CCP preamplifiers ensure minimum disturbancies to the sound field for accurate measurements in the full frequency range.

Click on the picture for more info.
Microphone Calibration System Type 90CA

Intelligent Pistonphone Type 42AP

With built-in barometric corrections and an LCD for displaying: sound pressure level, A-weighted sound pressure level, temperature in both °C and °F, ambient pressure in hPa.

And it has an RS-232 interface for extracting these data. Click on the picture for more info.

Pistonphone Type 42AP

Low noise level microphone systems

Low noise Level Microphone Systems Types 40HF and 40HH for measuring noise levels which lie below the threshold of hearing. Click picture for more info.

Low-noise Measurements

Preamplifier Type 26CF

With gain and filter switches. For selecting various combinations of gain and filtering. Gain can be set to either  0dB or +20 dB. Filtering can be set to A-Weighting, Linear or High-pass. Click in the picture for more info.

Preamplifier Type 26CF

Surface Microphone Type 40PS

Low-cost surface microphone for general purpose measurements on planar and curved surfaces. Wide useful frequency range reaching up to 20 kHz and a large dynamic range topping at around 136 dB. Click picture for more info.

Surface Microphone Type 40PS

Telephone Test Head Type 45AA

Tailor-made fixture for testing the acoustic performance of telephone handsets in accordance with international standards and recommendations.Can be set up for testing telephone handsets in accordance with ITU-T recommendations. Click picture for more info.

Telephone Test Head Type 45AA

Hearing-protector Fixture Type 45CA

For testing the performance of hearing-protection devices such as ear plugs and ear muffs. Conforms with ISO 4869-3 and can be used with one 1 or two 2 microphones or Ear Simulators for respectively monaural or binaural tests. Click picture for more info.

Hearing-protector Fixture Type 45CA

Ear and Cheek Simulator Type 43AG

For measurements on earphones of various types. It simulates the ear and cheek of a human head as well as approximating the acoustic impedance of an average human ear under certain circumstances within a given frequency band. Click picture for more info.

Ear and Cheek Simulator Type 43AG


Catalogue

CD-rom Catalogue

A revised and updated catalogue on CD-rom is available with numerous pictures of our products as well as charts showing typical setups for noise measurements, calibrations and ear/mouth testing.

Click on the picture if you would like a copy sent to you.

Catalogue
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Updated 22. february 2010

  US Office · 2285 East Enterprise Parkway · Twinsburg OH 44087 · Tel. 330 425 1201 · Fax 330 425 1235 · E-mail gras@gras.us