G.R.A.S. Sound & Vibration A/S products

Through a close cooperation with our customers, we know that data-safety is highly important because the costs related to unsuited and unreliable sensors may determine whether your project turns into a success or not. For our users, data safety translates directly into requests for easier microphone selection, simple system configuration and reduction of measurement errors. To meet these requirements, we invented the microphone set concept. It is simple, reliable and robust and consists of a microphone cartridge and preamplifier combination, which is calibrated as one unit. This eliminates errors because there is only one sensitivity value to account for and the risk of contaminating the interface is eliminated. Combine this with our unique and proven design and you have the most reliable measurement microphone sets available in the industry today.

Through a close cooperation with our customers, we know that data-safety is highly important because the costs related to unsuited and unreliable sensors may determine whether your project turns into a success or not. For our users, data safety translates directly into requests for easier microphone selection, simple system configuration and reduction of measurement errors. To meet these requirements, we invented the microphone set concept. It is simple, reliable and robust and consists of a microphone cartridge and preamplifier combination, which is calibrated as one unit. This eliminates errors because there is only one sensitivity value to account for and the risk of contaminating the interface is eliminated. Combine this with our unique and proven design and you have the most reliable measurement microphone sets available in the industry today.

GRAS 40AE is a high-precision electret condenser microphone made according to IEC 61094-4 requirements. The electret technology for microphones was introduced in the beginning of the 1960’s and has been continuously improved over the years. At GRAS, we have developed and refined our own techniques. This guarantees that our prepolarized microphones are as stable and robust as our traditional, externally polarized versions in daily use scenarios.

The broad working range and reliability has made 40AO-FV the preferred prepolarized microphone for coupler and ear simulator setups and is the natural supplement or replacement of existing solutions. It is used for production line testing in coupler setups for test of hearing aids, earphones, headphones, and headsets. The KEMAR Manikin can also be configured with 40AO-FV for wide-band binaural sound quality recordings.

The 41AC-4 is a small precision outdoor microphone according to IEC 61672-1 for monitoring of community noise and the noise of overhead aircraft.

The 41AC-3 is a small precision outdoor microphone according to IEC 61672-1 for monitoring of community noise and the noise of overhead aircraft.

The GRAS 1/2" Preamplifier 26CA-HT is similar to the GRAS 26CA Standard Preamplifier, but optimzed for use in high-temperature applications up to 120 °C (248 °F). It uses a CCP (Constant Current Power) supply, e.g. GRAS 12AL 1-Channel CCP Power Module with A-weighting filter. It has a very low inherent noise level, a large dynamic range and a frequency response from below 2 Hz to above 200 kHz. Its small ceramic thick-film substrate has a very high input impedance, and is shielded by a guard ring to minimise the influence of stray capacitance and microphonic interference. It has TEDS* according to IEEE P1451.4 for easy self identification and reading of calibration data. It has an integrated BNC output connector and can be used with all GRAS prepolarized microphones. The casing is made of stainless steel for maximum strength and durability.

GRAS26AI is a preamplifier designed for low-frequency applications in the laboratory and field and accommodates directly for all IEC 61094 standardized 1/2" externally polarized measurement microphones. It is rugged and reliable and can handle microphone signals up to 50 Vpeak within 1 Hz to 200 kHz. The printed circuit board is made by use of thick-film substrate technology and optimized with respect to maximum suppression of microphonics and moisture rejection. The high-quality, standard 7-pin LEMO male connector is integrated into the preamplifier and ensures that only one type of connector and cable is required for both connection and extension. 26AI is factory calibrated individually and delivered with a calibration chart stating its A-weighted and linear self-noise.

The GRAS 12AX is a constant current power module for powering 4 CCP preamplifiers/microphone sets. It is optimized for integration into a production environment. The anodized enclosure is sturdy and offers good protection against dirt, dust, and moisture. Except for the power switch, it has no external user controls. In this way unintended change of the gain settings is avoided.