GRAS rolls out Class 1 sound-intensity probe

The device is intended for high-reliability acoustic measurements across a variety of applications.

-- Test & Measurement World, 8/24/2010 7:00:00 AM

Danish manufacturer of acoustic-measurement products, GRAS Sound & Vibration, announced the North American debut of the Type 50GI, which it claims is the industry's only Class 1 prepolarized CCP (constant current powered) IEPE-type sound-intensity probe. The device is intended for high-reliability acoustic measurements across a variety of applications.

The Type 50GI probe is compatible with most industry-standard signal analyzers and IEPE-type data-acquisition devices. It is supplied in kit form with its own carrying case and shipped complete with all of the necessary supporting components for reliable sound-intensity measurements. These specially designed components include a phase-matched ½-in. prepolarized intensity-microphone set (Type 40GK), two ¼-in. CCP preamplifiers (Type 26CB), four solid interchangeable spacers, a windscreen, two BNC cables, and a probe handle.

The included pair of prepolarized CCP microphones meets IEC 61043 requirements for Class 1 intensity probes and incorporates a uniquely designed pressure-equalization system to ensure that phase characteristics are extremely well-defined. The microphones are calibrated along with two rugged ¼-in. CCP preamplifiers that are 40 mm long. Both microphones and preamplifiers feature a robust stainless-steel casing.

This added ruggedness minimizes sound-field disturbances otherwise brought about by shadow and diffraction effects across the full frequency range, with a symmetry that enables reliable calibrations as described in the proposed ISO/DIS 9614-2 standard for sound-power measurements using sound-intensity probes. For added durability, microphones and preamplifiers are swivel-head mounted onto the telescopic arm of the probe handle. The spacers allow microphones to be placed at varying lengths of 12 mm to 100 mm across a full frequency range of 50 Hz to 10 kHz and can be interchanged without dismantling the probe.

For more information about the Type 50GI CCP sound-intensity probe, go to www.gras.dk/00012/00056/00145.

GRAS Sound & Vibration, www.gras.dk.