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Summary of Contents for GRAS 50GI-R
- Page 1 Instruction Manual 50GI-R Sound Intensity Probe www.gras.dk LI0084 – Revision 6 June 2014...
- Page 2 Revision History Any feedback or questions about this document are welcome at gras@gras.dk. Revision Date Description 13 February 2013 First publication 19 June 2013 Revision - ordering information for spacers corrected 6 June 2014 New part numbers for spacers Copyright Notice ©...
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Page 3: Table Of Contents
Contents Introduction and Description ............4 Main Components ..................5 Handling and Assembling the Probe ..........8 The Microphones ..................8 Probe Design ..................... 8 Physical Strength ..................8 Assembling the Probe ................9 Calibration ................. 12 Checking the Sensivity and P-I Index using a Pistonphone ......12 Checking the Probe’s P-I Index using an Intensity Calibrator ...... -
Page 4: Introduction And Description
Introduction and Description The G.R.A.S 50GI-R Sound-intensity Probe is a two-microphone sound intensity probe. It has a pair of G.R.A.S. 40GK phase-matched ½" microphones, two G.R.A.S. 26CB ¼" phase-matched microphone preamplifiers, solid spacers, remote control handle and connection cable. The probe is adjustable, durable and fully complies with the following requirements: • IEC 61043, Electroacoustics - Instruments for the Measurement of Sound Intensity –... -
Page 5: Main Components
• Remote-control handle with (where applicable) up to two push buttons for controlling measurements The 50GI-R is delivered in a carrying case similar to the one shown in Fig. 2, complete with microphones, preamplifiers, standard accessories and a remote-control handle. - Page 6 (ISO/DIS 9614-2) for sound power measurements using sound-intensity measurements. 2 x Cable AA0084 26CB ¼" preamplifier Microdot Microdot male male Fig. 4. 26CB ¼" Preamplifier set supplied with 50GI-R and the 2 microdot cables. Cables AA0021 AC0024 12-pin LEMO male KE0132 Serial to USB...
- Page 7 Spacers To cover the wide frequency range (30 Hz - 10 kHz), Type 50GI-R Sound Intensity Probe is deliv- ered with four solid spacers of various lengths and a spacer cup Fig. 6. GR0040 RA0266 RA0265 RA0264 RA0263 Spacer cup...
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Page 8: Handling And Assembling The Probe
The connections between microphones and preamplifiers are very delicate. Therefore, the preamplifier threads of the 50GI-R are supported by stainless steel ½" to ¼" adapters. There is also a protective guard within the ¼" housing of each preamplifier. Furthermore, the microphones’... -
Page 9: Assembling The Probe
Assembling the Probe The Intensity Probe can be assembled in either a straight setup or a symmetrical setup: • The straight setup is for intensity measurements close to surfaces and general source location measurements. • The symmetrical configuration, is ideal for sound power measurements, for example according to the international standard ISO 9614-2 “Acoustics - Determination of sound power levels of noise sources using sound intensity”... - Page 10 Straight setup 26CB ¼” CCP Preamplifier Symmetrical setup RA0003 RA0001 Right- Straight Adapter angled Adapter 26CB ¼" CCP Preamplifier Spacer RA0266 40GK matched pair of micro- phones Spacer Cup GR0040 RA0001 Right-angled Adapter 26CB ¼" CCP Preamplifier Fig. 10. Exploded view of probe assembly for both straight and symmetrical setup. Assemble as follows: 1.
- Page 11 7. Assemble the probe head by pressing the free end of the spacer (mounted on the one micro- phone) into the spacer cup mounted on the other microphone: Push together Spacer cup Spacer Microphone Fig. 11. Assembling the probe head (shown for the symmetrical setup). 8.
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Page 12: Calibration
Calibration Checking the Sensivity and P-I Index using a Pistonphone Checking the Sensitivity Check the sensitivity of the microphones using a 42AP (recommended) or 42AA Pistonphone. Refer to the manual supplied with the pistonphone for instructions on using the pistonphone. Checking the P-I Index (Pressure Intensity) Check the P-I index using the RA0024 Two-port Calibration Coupler and a pistonphone, either the 42AP (recommended) or the 42AA. -
Page 13: Checking The Probe's P-I Index Using An Intensity Calibrator
Fig. 15. Setup with signal generator and sound intensity analyzer. 080001 Via a preamplifier power module (e.g. the GRAS 2-channel Power Module Type 12AQ) if the sound- intensity analyzer does not provide power for preamplifiers. White-noise, pink-noise or a sine wave. -
Page 14: Ordering Information
Ordering Information Included Items Part Number ½” Free-field Sound Intensity Microphone set 40GK ¼” CCP Preamplifier set 26CB Spacers: RA0263 Spacer, 100 mm Spacer, 50 mm RA0264 Spacer, 25 mm RA0265 Spacer, 12 mm RA0266 Straight adapter RA0003 Angled adapter RA0001 12-pin LEMO Extension Cable, 5 m (male-male) AA0021... -
Page 15: Specifications And Warranty
Warranty All G.R.A.S. products are made of high-quality materials that will ensure life-long stability and robustness. The 50GI-R is delivered with a 2-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.
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