Low-noise Microphone System 1/2″ Gras 40HL LEMO (10-16kHz)

Typical applications and use

• Measurements at very low sound pressurelevels
• Measurements on hard-disk drives, computerproducts, anechoic rooms, quiet rooms, etc
• Sound-power measurements at low levels

Design

• The 40HL comprises a special high-sensitive 1/2″ free-field measurement microphone and an integrated 1/2″ low-noise preamplifier. In combination, they connect to most high-quality input modules with LEMO 1B connector.
• It complies with IEC 61672 class 1.

Preamplifier

• The preamplifier, a true 1/2″ low-noise amplifIer with LEMO 1B connector, has a built-in compensation filter for free-field microphones.

Microphone

• The 1/2″ microphone is an externally-polarized free field microphone with a specially reduced inherent noise floor in order to achieve a high dynamic range and wide frequency range. Its diaphragm is specially tuned to yield high sensitivity coupled with low internal noise.

TEDS

• The preamplifier of the 40HL has TEDS according to IEEE 1451.4. If your measurement platform supports TEDS you can read and write data like properties and calibration data.

Operating 40HL

• For holding the microphone, you can order tripods and for level calibration of you need a pistonphone and Calibration Adapter attenuating the pistonphone signal to 94 dB re. 20 µPa. See the tab Ordering info.