G.R.A.S. 50VI-1 Vector intensity probe

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

Typical applications and use

  • Vector-intensity measurements
  • Soundfield mapping
  • Sound-source location
  • Near-field investigations

Design

The 50VI-1 complies fully with the requirements in IEC 61043, Electroacoustics - Instruments for the Measurement of Sound Intensity - Measurementswith Pairs of Pressure Sensing Microphones,1993 for Class 1 Sound-intensityprobes and the draft document ISO/DIS 11205.2.

The first generation of sound intensity probes was designed and developed using available standard microphones and preamplfiers; resulting in a number of compromises regarding size, acoustical performance and durability. In the new generation of sound-intensity probes, all components have been made specifically for sound intensity applications. Each small 1⁄4-inch diameter and 40mm long microphone preamplfier is housed in a robust, stainless steel casing which enables novel probe designs. These novel probe designs reduce the disturbances to the sound field otherwise brought about by the effects of shadows and diffraction, and its symmetry enables reliable calibrations as described in the standard (ISO/DIS 9614-2) for sound power measurements using sound-intensity measurements.

The Vector Intensity Probe Type 50VI includes spacers for 25 mm and 50 mm for covering the frequency range from 80 Hz to 6.3 kHz. The probe handle has an input for 6 preamplifiers and LEDs for indicating two states as well as a push button for remote control. The remote-controlled output can, for example, be connected to the RS232 port of a computer for controlling the process of data acquisition.

The output of the probe handle is a 24-pin LEMO connector and the 50VI includes a 5 m cable terminating in another 24-pin LEMO connector. This can be connected to a break-out adapter with six standard 7-pin LEMO microphone connectors for connection to the G.R.A.S. 12AC 6-Channel Power Module for G.R.A.S. Vector-intensity Probe.

The G.R.A.S. Vector Intensity Probe Type 50VI is available in two versions:

Version 1 is a full 3-dimensional vector intensity probe that includes three pairs of G.R.A.S. 40AI Sound-intensity microphones, three pairs of G.R.A.S. 26AA 1⁄4-inch Preamplifiers, 25 mm and 50 mm spacers, 6-channel probe handle, 5 m cable with LEMO connectors.

Version 2 is a 2-dimensional vector intensity probe that includes two pairs of G.R.A.S. 40AI Sound-intensity microphones, two pairs of G.R.A.S. 26AA 1⁄4-inch Preamplifiers, 25 mm and 50 mm spacers, 6-channel probe handle, 5 m cable with LEMO connectors.

Frequency range (±2 dB) Hz IEC 61043
Dynamic range lower limit (microphone thermal noise) dB(A) 25
Dynamic range upper limit dB 152
Set sensitivity @ 250 Hz (±2 dB) mV/Pa 25
Polarization voltage V 200
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 24-pin LEMO
CE/RoHS compliant/WEEE registered Yes/Yes/Yes
Weight g / oz 450 / 15.873

Included items

G.R.A.S. AA0030 10 m cable
G.R.A.S. AC0017 Y-cable adapter
G.R.A.S. AL0004 Small light weight microphone tripod

Optional accessories

G.R.A.S. 12AC 6-Channel Power Module for G.R.A.S. Vector-intensity Probe
G.R.A.S. AM0365 Windscreen for G.R.A.S. Vector-Intensity Probe