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Summary of Contents for GRAS 67HA
- Page 1 Instruction Manual G.R.A.S. 67HA 1 m Sound Power Hemisphere Kits www.gras.dk LI0106 – 10 November 2017...
- Page 2 Revision History Any feedback or questions about this document are welcome at gras@gras.dk. Revision Date Description 11 August 2014 First release 28 October 2015 Caution about the use of non-G.R.A.S. cables added to the section “Mounting Microphone Sets and Cables”...
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Page 3: Table Of Contents
Contents Introduction .................. 5 Standards ....................5 Applications ....................5 Plug & Play ....................5 Holders and Cables ................... 5 Delivered Items for 1 m Hemisphere ..........6 Hemisphere Structure ................. 6 4-channel Configurations ................7 10-channel Configurations ................8 20-channel Configurations ................ - Page 4 LI0106 – 10 November 2017...
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Page 5: Introduction
Standards The G.R.A.S. 67HA 1 m Sound Power Hemisphere is compliant with the ISO 3744, 3745 and 3746 (ANSI S12.54, S12.55, S12.56) standards and accommodate for 4, 10 and 20 microphone positions. These are clearly marked to ease the mounting and maintain measurement repeatability. -
Page 6: Delivered Items For 1 M Hemisphere
Delivered Items for 1 m Hemisphere The G.R.A.S. 67HA 1 m Hemisphere is delivered in two cases, one containing the parts for the structure, microphone holders, cables and cable clips, the other containing the parts for configur- ing the hemisphere with microphone sets and cables. -
Page 7: 4-Channel Configurations
3 x RA0259 28 mm 4 x GR1572 Top Microphone Cable Clip Holder 50 x KE0130 RA0261 G.R.A.S. 67HA- 01 with LEMO Microphone Sets ½" LEMO 10 m Cable Microphone Set LEMO to LEMO 4 x 46AF 4 x AA0009 Microphone Holder Spacer for incl. -
Page 8: 10-Channel Configurations
9 x RA0259 28 mm 10 x GR1572 Top Microphone Cable Clip Holder 50 x KE0130 RA0261 G.R.A.S. 67HA- 02 with LEMO Microphone Sets ½" LEMO 10 m Cable Microphone Set LEMO to LEMO 10 x 46AF 10 x AA0009 Microphone Holder Spacer for incl. -
Page 9: 20-Channel Configurations
Holder, 20 x RA0259 18 mm 4 x GR1571 Cable Clip 50 x KE0130 G.R.A.S 67HA-09 with Low Noise Microphone Sets ½" Low-noise 10 m Cable, Microphone Set LEMO to LEMO 20 x 40HL 20 x AA0009... -
Page 10: Assembling The Hemisphere - Overview
Assembling the Hemisphere – Overview The G.R.A.S. 1 m Hemisphere for sound power measurements consists of a basic structure common to all applications. This structure can be configured for 4-channel, 10-channel and 20-channel measurements. Below is shown a quick overview of the assembly of the hemisphere and the mounting of microphones for a 10-channel configuration. - Page 11 Fig. 3. The assembled structure ready for configuration. Fig. 4. The hemisphere structure mounted with microphones and cables for a 10-channel setup. LI0106 – 10 November 2017...
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Page 12: Assembling The Hemisphere Structure
Assembling the Hemisphere Structure Introduction The Hemisphere consists of a ground layer and vertical and horizontal poles: • The ground layer consists of six feet and six connecting strips. • The A-layer consists of six vertical poles attached to the feet, labeled A1 to A6. • The horizontal circle consists of six poles and six 4-pole connecting pieces. - Page 13 Assembling the Ground Layer Strip for ground layer Tube for strips and Hole for securing the foot poles. Outer diam- to the floor, 6 mm (not eter for strips, inner included) for vertical poles of Finger screw for securing A-layer the vertical pole Fig.
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Page 14: Assembling The A-Layer (Bottom)
Assembling the A-Layer (Bottom) Fig. 9. The A-layer vertical poles mounted in the feet. Mounting the Vertical Poles and 4-pole Connecting Pieces 1. Slide the vertical pole labeled A1 with the label end upwards into one of the feet. 2. Tighten the finger screw lightly to assure some clearance for angular adjustment of poles and connecting pieces in the next steps. -
Page 15: Assembling The B-Layer (Top)
Assembling the B-Layer (Top) Fig. 11. The 1m Hemisphere with all vertical poles assembled. Mounting the Vertical Poles and the top Connecting Piece 1. Slide the six vertical poles B1 to B6 into the 4-pole connecting pieces with the labeled end pointing upwards, and tighten lightly. -
Page 16: Assembling The Circle
Assembling the Circle Fig. 13. First step of the assembly of the circle. Assembling the Circle The circle consists of six identical poles. Their purpose is solely to stabilize the structure and they can therefore be sequenced at will. When finished, the structure will look as shown in Fig. 15. 1. -
Page 17: Finishing The Assembly Of The Structure
Finishing the Assembly of the Structure When all poles and connecting pieces have been assembled, you need to fine adjust the orienta- tion of all poles and tighten all finger screws. When mounted correctly, the hemisphere will present a smooth structure with a level horizontal circle and smooth vertical curves. -
Page 18: Mounting Microphone Sets And Cables
Mounting Microphone Sets and Cables Mounting the Microphone Holders The hemisphere is designed for easy and repeatable 4-channel, 10-channel and 20-channel measurements: • Clearly marked mounting points make it easy to mount the microphone sets in accordance with the ISO and ANSI standards. • A flexible mounting system with adjustable holders and fixed spacers makes it easy to mount the microphone sets with the correct distance and angle to the hemisphere’s center. - Page 19 Holders and Spacers For all configurations, the same type of microphone holder is used. Spacers of different lengths are used to ensure that the three types of microphone sets – CCP , LEMO and LEMO Low-noise – can be mounted with the correct distance to the center. Microphone Set Spacer 46AE (CCP)
- Page 20 Mounting a Microphone Holder at the Top Center Fig. 17. For 4 and 10-channel configurations, the top microphone holder is attached to the top connector. 1. Screw the long top spacer onto the stud screw on the 6-pole connecting piece. 2.
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Page 21: Mounting Microphone Sets And Cables
Mounting Microphone Sets and Cables The microphone sets are push fitted into the microphone holders until they bottom out. The slit in the lower part of the holder is used for the cable. The cables are fastened to the hemisphere poles with wire clips. -
Page 22: Technical Specifications
Technical Specifications Dimensions incl. Feet Diameter 2714 mm Height 1285 mm G.R.A.S. 46AE 1/2” CCP Standard Microphone Sets Frequency Range 3.15 Hz – 20 kHz Dynamic Range 17 dBA – 138 dB Sensitivity 50 mV/Pa G.R.A.S. 46AF 1/2” LEMO Standard Microphone Sets Frequency Range 3.15 Hz –... -
Page 23: Ordering Information
Ordering Information 4-Channel Hemispheres (ISO 3746:2010/ANSI S12.56) G.R.A.S 67HA-04 1 m 4 ch. CCP Sound Power Hemisphere Included Items Part Number 1 m Hemisphere Structure AL0024-4 G.R.A.S. ½" CCP Standard Microphone Set 46AE 10 m BNC Cable* AA0037 Microphone Holder... -
Page 24: 10-Channel Hemispheres
10-Channel Hemispheres (ISO 3744:2010/ANSI S12.54) G.R.A.S 67HA-05 1 m 10 ch. CCP Sound Power Hemisphere Included Items Part Number 1 m Hemisphere Structure AL0024-5 G.R.A.S. ½” CCP Standard Microphone Set 46AE 10 m BNC Cable* AA0037 Microphone Holder RA0259 Microphone Holder Spacer, 28 mm... -
Page 25: 20-Channel Hemispheres
20-Channel Hemispheres (ISO 3745:2010/ANSI S12.55) G.R.A.S 67HA-06 1 m 20 ch. CCP Sound Power Hemisphere Included Items Part Number 1 m Hemisphere Structure AL0024-6 G.R.A.S. ½" CCP Standard Microphone Set 46AE 10 m BNC Cable* AA0037 Microphone Holder RA0259 Micophone Holder Spacer, 28 mm... -
Page 26: Accessories
Accessories Item Part Number Pair of flight cases, with foam inserts RA0276 G.R.A.S. Multifunction Sound Calibrator (94 dB and 114 dB) 42AG G.R.A.S. Intelligent Pistonphone (114 dB) 42AP G.R.A.S. 94dB Pistonphone Coupler for G.R.A.S. 42AP RA0090 Cable for CCP Microphone Sets, custom length, XXXX = custom length in centimeters AA0039- CLXXXX Cable for LEMO Microphone Sets, custom length, XXXX = custom length in centimeters AA0020-CLXXXX... -
Page 27: Calibration, Warranty And Service
Calibration, Warranty and Service All included microphone sets are delivered with individual calibration charts including sensitivity values and frequency responses. These sensitivity values can be used directly in your system setup. Verification and Calibration For measurement chain verification, a reference sound source will be required. G.R.A.S. supplies 114 dB Sound Calibrators and Pistonphones for the standard microphone sets and a special 94 dB Pistonphone Coupler for the low-noise microphone sets.
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