G.R.A.S. 50AI-LP 1/2" CCP Rugged Intensity Probe

Freq range: IEC 61043 Class 1
Dyn range: 25 dB(A) to 152 dB
Sensitivity: 12.5 mV/Pa

This product is only available through the Siemens Software Industry’s sales channel. Please find your reseller here.

Typical applications

  • Sound-power measurements
  • Sound-source location and ranking
  • Sound Intensity mapping


The G.R.A.S. 50AI-LP 1/2" CCP Rugged Intensity Probe is a sound intensity probe for direct connection to LMS data acquisition modules with ICP inputs.

The probe includes a pair of phase matched prepolarized measurement microphones that meet the requirements of IEC standard 61043 for a class-1 intensity probe. The small rugged ¼" CCP preamplifiers ensure minimum disturbances to the sound field for accurate measurements in the full frequency range.

The probe set includes solid interchangeable spacers for microphone separation. These spacers can be easily interchanged without dismantling the probe.

The 50AI-LP comes with spacers from 12 mm to 50 mm so that the probe can cover the frequency range from 80 Hz to 10 kHz.

All components are made specifically for sound intensity applications. Both small ¼" diameter by 40 mm long microphone preamplifiers are housed in robust, stainless steel casings. This enables novel probe designs for reducing disturbances to the sound field otherwise brought about by the effects of shadows and diffraction, and a symmetry that enables reliable calibrations as described in the proposed standard (ISO/DIS 9614-2) for sound power measurements using sound intensity measurements.

The microphone is a ½” free-field prepolarized microphone with a uniquely designed pressure equalisation system that ensures extremely well defined phase characteristics.

The microphone and preamplifier are mounted on a swivel head on the telescopic arm of the handle. This flexible solution allows measurements very close to the sound source.

The very robust probe head of the 50AI-LP is optimized for heavy use in the field.

The 50AI-LP is assembled and tested by G.R.A.S. before leaving the factory. An individual test certificate is included.


Before leaving the factory, all G.R.A.S. products are calibrated in a controlled laboratory environment using traceable calibration equipment. We recommend a yearly recalibration at minimum, depending on the use, measurement environment, and internal quality control programs. We recommend calibration prior to each use to ensure the accuracy of your measurements.


All G.R.A.S. products are made of high-quality materials that will ensure life-long stability and robustness. The 50AI-LP is delivered with a 5-year warranty.

Damaged diaphragms in microphones can be replaced. The warranty does not cover products that are damaged due to negligent use, an incorrect power supply, or an incorrect connection to the equipment.

For more information, contact your G.R.A.S. representative.

Service and Repair

All repairs are made at G.R.A.S. International Support Center located in Denmark. Our Support Center is equipped with the newest test equipment and staffed with dedicated and highly skilled engineers. Upon request, we make cost estimates based on fixed repair categories.

If a product covered by warranty is sent for service, it is repaired free of charge, unless the damage is the result of negligent use or other violations of the warranty. All repairs are delivered with a service report, as well as an updated calibration chart.

Frequency range (±2 dB) Hz Ref. IEC 61043 Class 1
Dynamic range lower limit (microphone thermal noise) dB(A) 25
Dynamic range upper limit dB 152
Set sensitivity @ 250 Hz (±2 dB) mV/Pa 12.5
Polarization voltage V 200V
Microphone venting Rear
Temperature range, operation °C / °F 5 to 40 / 41 to 104
Temperature coefficient @250 Hz dB/°C / dB/°F -0.01
Humidity range non condensing % RH 0 - 100
Humidity coefficient @250 Hz dB/% RH -0.001
Influence of axial vibration @1 m/s² dB re 20 µPa 66
Connector type 12-pin LEMO
CE/RoHS compliant/WEEE registered Yes/Yes/Yes
Weight g / oz 400 / 14.110
G.R.A.S. Sound & Vibration reserves the right to change specifications and accessories without notice.


G.R.A.S. RA0213 Rugged Probe Head
G.R.A.S. 40GK 1/2"' Intensity Microphone Set
G.R.A.S. RA0001 Right-angled (90º) Adapter for 1/2" microphone and 1/4" preamplifier
G.R.A.S. GR0040 Holder for spacer
G.R.A.S. RA0264 Spacer, 50 mm
G.R.A.S. RA0265 Spacer, 25 mm
G.R.A.S. RA0266 Spacer, 12 mm
G.R.A.S. 26CC Set 1/4" CCP Preamplifier set
G.R.A.S. AA0021 5 m Extension Cable, 5 m, 12 pin LEMO male - male
G.R.A.S. AC0022 Adapter cable, 12-pin LEMO to  2 x BNC + USB Adapter
G.R.A.S. AA0068 2 x SMB to Microdot cable, 25 cm (male-male)
G.R.A.S. AI0048S Probe handle
G.R.A.S. AM0376 Windscreen


G.R.A.S. AA0010-S1 3 m LEMO 12-pin - Lemo 12-pin, Cable for Intensity Probe
G.R.A.S. AA0010 10 m LEMO 12-pin - Lemo 12-pin, Cable for Intensity Probe
G.R.A.S. 51AB Intensity Calibrator
G.R.A.S. 42AP Pistonphone with built-in barometerand thermometer (recommended)
G.R.A.S. 42AA Pistonphone
G.R.A.S. RA0024 Two-port Calibration Coupler (for G.R.A.S. 42AP or 42AA Pistonphones)
G.R.A.S. 51AC Sound Intensity Calibration Kit for 50AI-LP
G.R.A.S. Sound & Vibration reserves the right to change specifications and accessories without notice.