CCP Free-field Standard Microphone Set GRAS 1/2″ 46AZ (0.5-20kHz)

Introduction

• 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.

Typical applications and use

• The 46AZ is a free-field microphone set and as such optimized for all acoustic applications, where the location of the main sound source is known and the microphone can be pointed directly at it ensuring 0° incidence.
• The low frequency range makes it ideal for measuring low frequency sound from e.g. wind mills.
• Regarding temperature range, see the Specifications. Should higher temperature limits be required, we recommend considering  the GRAS probe microphones where the microphone and preamplifier can be isolated from the hot source.

Design

• The GRAS 46AZ is a high-performance 1/2” free-field standard microphone set for measuring medium sound pressure levels at medium frequencies. In our clean-room environment the set is assembled and sealed with a label. However, the microphone set can be dismounted, if  you wish to use the components separately.

Microphone

• The microphone cartridge is the high-quality IEC  61094 WS3F standardized GRAS 40AZ 1/2″ Prepolarized Free-Field Microphone, designed for long-term reliability in multiple environments.
• The prepolarization is obtained through an electret that is inflicted on the microphone back-plate under highly controlled conditions. The electret is then charged to match the specified microphone sensitivity.

Preamplifier

• The preamplifier is the GRAS 26CI 1/2″ CCP Standard Preamplifier with BNC connector, and based on our well-known circuit board substrates. In the industry these are famous for their low self-noise, wide frequency and excellent slew rate performance.

Compatibility

• To perform as specified the GRAS 46AZ microphone set requires a constant current input module that can deliver 4 mA and 24 V unloaded CCP voltage supply. If the constant current supply is lower, the capability of driving long cables is reduced and consequently the upper frequency is reduced. If the voltage supply is lower it will influence the upper dynamic range.
• The microphone set is terminated with a  BNC connector. Ready to use coax cable assemblies of various types and lengths are available in standard as well as customized lengths.
• The 46AZ is IEEE 1451.4 TEDS v. 1.0 compliant. If your measurement platform supports Transducer Electronic Data Sheets you will be able to read and write data like properties and calibration data.

System verification

• The functionality of TEDS is very useful to determine which microphone is connected to which input channel. However, it is not a check of whether the microphone is within specifications or not. For daily verification and check of your measurement setup, we therefore recommend using a sound source like the GRAS 42AG Sound Calibrator.
• For proper sensitivity calibration we recommend using a reference sound source like the GRAS 42AP Intelligent Pistonphone.