Microphone Specifications

Brüel & Kjær’s microphones are developed by a dedicated team of engineers with comprehensive acoustic knowledge, material physics knowledge, and a deep understanding of sophisticated production processes.

MICROPHONE HANDBOOK
DOWNLOAD PDF
BY BRÜEL & KJÆR

DOWNLOAD NOW

Brüel & Kjær’s microphones are developed by a dedicated team of engineers with comprehensive acoustic knowledge, material physics knowledge, and a deep understanding of sophisticated production processes. Each Brüel & Kjær microphone has excellent long-term stability and robustness.

It is virtually unaffected by environmental factors because Brüel & Kjær quality is built into it by every single well-defined production process and every single operator who is proud of his/her work.

If you know your requirements, our microphone selection filter can help you choose the microphone you need.

Otherwise, this is a list of general measurement microphone requirements for your consideration.

Good acoustic and electric performance:

• Wide frequency range and flat frequency response
• Wide linear dynamic range, low inherent noise levels, signal to noise ratio, and low distortion
• Low influence on the sound field to be measured

Minor influence from the environment:

• Low influence from ambient pressure, temperature, and humidity
• Low influence from vibration, magnetic and electromagnetic fields
• Good mechanical robustness, good bump, and shock resistance
• Good chemical resistance, and good corrosion resistance

High stability of microphone sensitivity and frequency range:

• Small short term fluctuations (random changes)
• Small long term drift (systemic change)
• Small high-temperature drift (systemic change)

High suitability for measurement and calculation of properties:

• Suitable for calibration using practical/accurate methods
• Simple shapes and easy-to-describe dynamic system parameters

Comprehensive microphone specifications and performance description:

• Availability of measured and calculated microphone type data
• Performance documentation by an individual calibration chart
• Availability of service for re-calibration

Consider your Microphone Requirements

When selecting a microphone, one or more of the following main parameters need to be considered.

Relevant standards for measurement microphones:

• IEC 651: Sound Level Meters
• IEC 1094: Measurement Microphone Part 1: Specifications for laboratory standard microphones, Part 4: Specifications for working standard microphones
• ANSI S1.4: Sound Level meters
• ANSI S1.12: Measurement Microphones Type L: Reference, Type XL: As is but no outside diameter specified, Type M: Sound Pressure Magnitude, Type H: Small diffraction Errors.

LEARN MORE
MEASUREMENT MICROPHONES

Sound field (polar pattern) - suited to your measurements

Frequency range – what frequency range you want to measure

Dynamic range – what sound pressure level you want to measure

Other parameters to consider

Microphone venting – if the microphone is going to be flush mounted

Phase response – if the microphones are going to do sound intensity measurement or array measurements

Polarization – if you want to measure at high temperature, high humidity, or just want to use your most standard data acquisition system with other CCLD transducers

Environment – especially the temperature, humidity, and atmosphere of the location where the measurement is going to be conducted

It should be stressed that many of the parameters are inter-dependent, such as the frequency range and the dynamic range are inter-dependent, which is illustrated by the below figures. Thus, selection considerations cannot be taken in isolation.

For example, if you are going to measure at very high frequencies, your microphone selection will be limited to ones with a high lower limit of dynamic range. This will land on either a 1/4" or a 1/8” microphone depends on the upper limiting frequency, you need.

Graph showing relationship between upper limiting frequency range and inherent noise. The four “dots” represent the four sizes of the microphone in order from 1” (top left) to ⅛” (top right)

Upper limiting frequency response of four typical measurement microphones in different sizes.

The dynamic range of the same 4 measurement microphones as the previous figure. The lower limit is given in dB(A). The upper limit is given in dB at the level at which 3% total harmonic distortion occurs.

After selecting your microphones, correct handling will prolong their lifespan dramatically.

How to handle it? Here are the best practices for handling and cleaning condenser microphones.

If you want to know more about microphones, such as microphone theory, characteristics of microphones and preamplifiers, selecting a microphone and calibration, Brüel & Kjær Microphone Handbook is your best starting point. Happy reading!