Main Menu

See All Acoustic End-of-Line Test Systems See All DAQ and instruments See All Electroacoustics See All Software See All Transducers See All Vibration Testing Equipment See All Academy See All Resource Center See All Applications See All Industries See All Insights See All Services See All Support See All Our Business See All Our History See All Our Sustainability Commitment See All Global Presence

Main Menu

See All Actuators See All Combustion Engines See All Durability See All eDrive See All Production Testing Sensors See All Transmission & Gearboxes See All Turbo Charger See All Industrial electronics See All S&V Signal conditioner See All DAQ Systems See All Power Analyser See All S&V Hand-held devices See All High Precision and Calibration Systems See All Test Solutions See All nCode - Durability and Fatigue Analysis See All ReliaSoft - Reliability Analysis and Management See All Test Data Management See All DAQ Software See All Drivers & API See All Utility See All Vibration Control See All Acoustic See All Current / voltage See All Displacement See All Load Cells See All Pressure See All Strain Gauges See All Vibration See All Torque See All LDS Shaker Systems See All Vibration Controllers See All Power Amplifiers See All Accessories for Vibration Testing Equipment See All Training Courses See All Acoustics See All Asset & Process Monitoring See All Custom Sensors See All Data Acquisition & Analysis See All Durability & Fatigue See All Electric Power Testing See All NVH See All Reliability See All Smart Sensors See All Vibration See All Weighing See All Automotive & Ground Transportation See All Calibration See All Installation, Maintenance & Repair See All Support Brüel & Kjær See All Release Notes See All Compliance See All Our People

Main Menu

See All QuantumX See All LAN-XI See All SomatXR See All MGCplus See All CANHEAD See All Optical Interrogators See All GenHS See All API See All Microphone Cartridges See All Microphone Sets See All Microphone Pre-amplifiers See All Sound Sources See All Acoustic Calibrators See All Special Microphones See All Accessories for acoustic transducers See All Experimental testing See All Transducer Manufacturing (OEM) See All CCLD (IEPE) accelerometers See All Charge Accelerometers See All Rotating See All Non-rotating (calibration) See All Electroacoustics See All Noise Source Identification See All Environmental Noise See All Sound Power and Sound Pressure See All Noise Certification See All Industrial Process Control See All Structural Health Monitoring See All Electrical Devices Testing See All Electrical Systems Testing See All Grid Testing See All High-Voltage Testing See All Vibration Testing with Electrodynamic Shakers See All Structural Dynamics See All Machine Analysis and Diagnostics See All Dynamic Weighing See All Calibration Services for Transducers See All Calibration Services for Handheld Instruments See All Calibration Services for Instruments & DAQ See All On-Site Calibration See All Resources See All Software License Management

Microphone Selection Guide

Choosing the right microphone is not an easy task and choosing an inappropriate microphone can lead to measurement errors. This easy microphone selection guide should help if you’re not sure which microphone you need.
Transducer icon

Once the frequency range and sound level range of interest is defined, the next question to ask is, “Where will I use my microphone?”. For most uses, the type of sound field is the main parameter to consider. 

The concept of the acoustic field is explained in our related article Measurement Microphones Explained and in the Brüel & Kjær Microphone Handbook - available for free download.

Microphone Sound Field

  • Free-field microphone: Measurements outdoors or in an anechoic chamber.
  • Diffuse-field microphone: Measurements inside - i.e., within a car cabin, you will need an (a ½-inch free-field would underestimate the sound pressure about 6 dB at 20 kHz)
  • Pressure-field microphone: Measurements performed in small, closed couplers. As an example, to measure headphone performance, or close to hard, reflective surfaces.

microphone selection guide

Specialized Microphones

For specialized measurement applications, Brüel & Kjær provide several models to choose from:

Transducer icon

  • Very high- and ultra-low frequency measurements require microphones specially designed for one extreme or the other - but never both. Microphone type 4964 and type 4193 are perfect for ultra-low-frequency measurements. However, for the very high-frequency end you will need a microphone like Type 4138 is needed (up to 140 kHz)
  • Extremely high-pressure sound levels require a robust microphone such as microphone type 4941. Inflow measurements may require a flush-mounted or small-footprint microphone like microphone type 4948 or type 4949
  • Particularly small spaces, awkward placements, or harsh environments can also require specialized microphones. Type 4182 is a good start – its design provides a very high acoustic impedance probe tip (to minimize the effect on the measurement) and it can be used to measure in temperatures up to 700°C

Microphone Polarization

Prepolarized or externally polarized?

In most cases, once you have defined the application, you can refine and choose between

Finally, remember that choosing a microphone with a larger membrane will generally lower the inherent noise and increase the sensitivity, while microphones with a smaller membrane will be able to measure higher sound pressure levels, have an extended frequency range and be less sensitive to the angle of incidence of the incoming sound wave.

Microphone position