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Instruction Manual  

67AX and 67AD CCP Ground Microphone System   |   4

Introduction

This manual describes how to assemble and calibrate the 67 series ground array sets:

• 

67AX ½” CCP fl ush-mounted microphone, low sensitivity 

• 

67AD ½” CCP fl ush-mounted microphone, high sensitivity

Delivered Items

The following table lists the items included with the 67series package.

Set

Item

Part Number

67AX

½” CCP fl ush-mounted microphone, with 3 m cable

47AX-S1

67AD

½” CCP fl ush-mounted microphone, with with 3 m cable

47AD-S1

O-ring, Ø13.5 mm 

OR0137

O-ring, Ø55 mm

OR1512

Cover plate, with 8 screws (SK2015 M2.00 × 4.00)

GR1426

Cable safety clip, with 2 screws (SK2008 M3.00 × 8.00)

GR1427

Mounting plate

GR1425

Windscreen 

AM0375

Optional Items

Set

Item

Part Number

Calibration Adapter Holder Kit for sensitivity calibration

RA0216

Electrostatic Actuator Connector Kit for frequency calibration

RA0310

Summary of Contents for 67AD

Page 1: ...Instruction Manual GRAS 67AX and 67AD Ground Array Microphone Systems LI0055 4 December 2018 ...

Page 2: ... Vibration A S is not liable or responsible for any errors or inaccuracies that may appear in this document Trademarks Any other product names mentioned in this document may be trademarks or registered trade marks of their respective companies and are hereby acknowledged Revision History Any feedback or questions about this document are welcome at gras gras dk Revision Date Description 1 27 May 20...

Page 3: ...67 Series System 5 Calibration 6 In situ Level Calibration 6 On site Frequency Calibration 7 Seperate Level Calibration after Dismantling 7 Technical Specifications 8 Dimensions and Data for 67AX 8 Dimensions and Data for 67AD 9 Ordering Information 10 Accessories 10 Warranty and Repair 10 Calibration 10 Warranty 10 Service and Repairs 10 ...

Page 4: ...th the 67series package Set Item Part Number 67AX CCP flush mounted microphone with 3 m cable 47AX S1 67AD CCP flush mounted microphone with with 3 m cable 47AD S1 O ring Ø13 5 mm OR0137 O ring Ø55 mm OR1512 Cover plate with 8 screws SK2015 M2 00 4 00 GR1426 Cable safety clip with 2 screws SK2008 M3 00 8 00 GR1427 Mounting plate GR1425 Windscreen AM0375 Optional Items Set Item Part Number Calibratio...

Page 5: ... of the small O ring Arrange the cable attached to the microphone in the cavity surrounding the mounted micro phone and fit the cable in the ridge that leads to the outer edge of the plate 3 Place the large O ring in the ridge near the edge of the cavity The large O ring must lie on top of the cable 4 Fit the cover plate on top of the microphone and O ring assembly and fasten in place with 8 screws...

Page 6: ...pter Kit GRAS Pistonphone 42AP or 42AA Procedure 1 Mount the calibration adapter it as shown below 2 Hold the pistonphone steady while centering the opening in the adapter over the microphone 3 Gently press the pistonphone over the adapter ensuring that it is as far in the pistonphone as it will go Also ensure that you hold the pistonphone upright G R A S Pistonphone Type 42AP Serial No XXXXX IEC ...

Page 7: ... calibration 14AA Actuator Supply Power G R A S Actuator Supply Type 14AA AC Output 200VDC AC Output Max 1Vrms 800VDC AC Output On GND AC Input Overload Signal generator RA0310 Actuator Connector Ground plate Fig 3 Mounting and connecting the RA0310 Actuator Connector Separate Level Calibration after Dismantling The microphone can be calibrated separately after dismounting from the ground plate Fo...

Page 8: ... set at 250 Hz 12 5 mV Pa Polarization voltage 0 V Dynamic range for the set Upper limit 3 distortion 150 dB re 20 µPa Thermal noise 22 dB A re 20 µPa Temperature Operation 30 C to 70 C 22 F to 158 F Storage 40 C to 85 C 40 F to 185 F Temperature coefficient 0 01 dB C Static pressure coefficient 250 Hz 25 C 0 008 dB kPa Humidity non condensing Range 0 100 RH Influence 250 Hz 0 1 dB 0 100 RH Influence of...

Page 9: ...z 50 mV Pa Polarization voltage 0 V Dynamic range for the set Upper limit 3 distortion 138 dB re 20 µPa Thermal noise 18 dB A re 20 µPa Temperature Operation 30 C to 70 C 22 F to 158 F Storage 40 C to 85 C 40 F to 185 Temperature coefficient 0 01 0 006 dB C Static pressure coefficient 250 Hz 25 C 0 008 dB kPa Humidity non condensing Range 0 100 RH Influence 250 Hz 0 1 dB 0 100 RH Influence of axial vibr...

Page 10: ...n TEDS Warranty All GRAS products are made of high quality materials that will ensure life long stability and robustness The 67AX 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 Service and Repairs All repairs are mad...

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