GRAS 46AO 1/2'' CCP Pressure Standard Microphone Set

Freq range: 3.15 Hz to 20 kHz
Dyn range: 25 dB(A) to 150 dB
Sensitivity: 12 mV/Pa

Technology

Introduction

Through a close cooperation with our customers, we know that data-safety is highly important because the costs related to unsuited and unreliable sensors may determine whether your project turns into a success or not.

For our users, data safety translates directly into requests for easier microphone selection, simple system configuration and reduction of measurement errors.

To meet these requirements, we invented the microphone set concept. It is simple, reliable and robust and consists of a microphone cartridge and preamplifier combination, which is calibrated as one unit. This eliminates errors because there is only one sensitivity value to account for and the risk of contaminating the interface is eliminated. Combine this with our unique and proven design and you have the most reliable measurement microphone sets available in the industry today.

Typical applications and use

The 46AO is a high-precision microphone suitable for laboratory work.

Regarding temperature range, see the Specifications. Should higher temperature limits be required, we recommend considering  the GRAS probe microphones where the microphone and preamplifier can be isolated from the hot source.

Design

The GRAS 46AO is a high-performance standard microphone set. In our clean-room environment the set is assembled and sealed with a label. However, the microphone set can be dismounted, if you wish to use the components separately.

Microphone
The microphone cartridge is the high-quality IEC  61094 WS2P standardized GRAS 40AO 1/2" Prepolarized Pressure Microphone, designed for long-term reliability in multiple environments.

Preamplifier
The preamplifier is the GRAS 26CA Preamplifier which is inclusive TEDS and based on our well-known circuit board substrates. In the industry these are famous for their low self-noise, wide frequency and excellent slew rate performance.

46AO is rear-vented, but it is also available in a front-vented version, 46AO-FV. 

Compatibility

To perform as specified the GRAS 46AO microphone set requires a constant current input module that can deliver 4 mA and 24 V unloaded CCP voltage supply. If the constant current supply is lower, the capability of driving long cables is reduced and consequently the upper frequency is reduced. If the voltage supply is lower it will influence the upper dynamic range.

The microphone set is terminated with a BNC connector. Ready to use coax cable assemblies of various types and lengths are available in standard as well as customized lengths.

The 46AO is IEEE 1451.4 TEDS v. 1.0 compliant. If your measurement platform supports Transducer Electronic Data Sheets you will be able to read and write data like properties and calibration data.

System verification

The functionality of TEDS is very useful to determine which microphone is connected to which input channel. However, it is not a check of whether the microphone is within specifications or not. For daily verification and check of your measurement setup, we therefore recommend using a sound source like the GRAS 42AG Sound Calibrator.

For proper sensitivity calibration we recommend using a reference sound source like the GRAS 42AP Intelligent Pistonphone.

Service

Should you by mistake damage the diaphragm on a GRAS microphone we will in most cases be able to exchange it at a very reasonable cost and short turn-around time. This not only protects your investment but also meets your quality assurance department since you do not have to worry about new serial numbers etc.

Calibration

When leaving the factory, all GRAS microphones have been calibrated in a controlled laboratory environment using traceable calibration equipment. Depending on the use, measurement environment and internal quality control programs we recommend that the microphone is recalibrated at least once a year.

We offer two kinds of calibration as an optional after-sales service: GRAS Traceable Calibration and GRAS Accredited Calibration.

GRAS Traceable Calibration is a traceable calibration performed by trained personnel under controlled conditions according to established procedures and standards. This is identical to the rigorous calibration that all GRAS microphones are subjected to as an integral part of our quality assurance.

GRAS Accredited Calibration is performed by the GRAS Accredited Calibration Laboratory that has been accredited in accordance with ISO 17025 by DANAK, the Danish Accreditation Fund.

If you want a new microphone set delivered with an accredited calibration in stead of the default factory calibration, specify this when ordering.

Learn more at gras/calib.

Quality and warranty

GRAS microphone sets are made of components from our proven standard portfolio and are all manufactured of high-quality material and branded parts that were chosen and processed to ensure life-long stability and robustness.

All parts are manufactured and assembled at the factory in Denmark by skilled and dedicated operators in a verified clean-room environment. The microphone diaphragm, body and unique protection grid are made of high-grade stainless steel and make the microphone set resistant to physical damage as well as corrosion caused by aggressive air or gasses.

This, together with the enforced gold-plated microphone terminal guarantees a highly reliable connection. Thanks to the high quality, our warranty against defective materials and workmanship is 5 years.

Specifications

Frequency range (±1 dB)
Hz
5 to 12.5 k
Frequency range (±2 dB)
Hz
3.15 to 20 k
Dynamic range lower limit with GRAS preamplifier
dB(A)
25
Dynamic range upper limit with GRAS CCP preamplifier
dB
150
Set sensitivity @ 250 Hz (±3 dB)
mV/Pa
12
Set sensitivity @ 250 Hz (±3 dB)
dB re 1V/Pa
-38.5
Output impedance
Ω
<50
Output Voltage Swing, min. @ 24-28 V CCP voltage supply
Vp
8
Power supply min. to max.
mA
2 to 20
Power supply min. to max. (single/balanced)
V
N/A
DC bias voltage, typ.
V
12
Microphone venting
Rear (Front on request)
IEC 61094-4 Compliance
WS2P
Temperature range, operation
°C / °F
-30 to 70 / -22 to 158
Temperature range, storage
°C / °F
-40 to 85 / -40 to 185
Temperature coefficient @250 Hz
dB/°C / dB/°F
-0.01 / -0.006
Static pressure coefficient @250 Hz
dB/kPa
-0.007
Humidity range non condensing
% RH
0 to 95
Humidity coefficient @250 Hz
dB/% RH
-0.001
Influence of axial vibration @1 m/s²
dB re 20 µPa
66
TEDS UTID (IEEE 1451.4)
27 v. 1.0
Connector type
BNC
CE/RoHS compliant/WEEE registered
Yes/Yes/Yes
Weight
g / oz
33 / 1.164
Specification Conditions

GRAS Sound & Vibration reserves the right to change specifications without notice.

Typical frequency response.

Free-field corrections for different angles of incidence

Dimensions

Ordering info

 Optional items

GRAS 46AO-FV

1/2'' CCP Pressure Standard Microphone Set, Front Vented

GRAS AA0035

3 m BNC - BNC Cable

GRAS AA0039-CL

Customized length BNC - BNC Cable

GRAS AL0008

1/2" Microphone Holder, POM

GRAS AL0012

1/2" Microphone Holder, Stainless Steel

GRAS AL0005

Swivel head

GRAS AL0006

Tripod

GRAS RA0020

1/2" Nosecone

GRAS AM0069

Windscreen for 1/2" Microphones

GRAS RA0131

1/2'' Rain protection cap

GRAS 12AL

1-Channel CCP Power Module with A-weighting filter

GRAS 12AQ

2-Channel Universal Power Module with signal conditioning and PC interface

GRAS 42AG

Multifunction Sound Calibrator, Class 1

GRAS 42AP

Intelligent Pistonphone, Class 0

GRAS CA0029

Traceable Calibration of Microphone Set

GRAS CA2301

Accredited Calibration of Microphone Se

GRAS Sound & Vibration reserves the right to change accessories without notice.

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