The Measurement Microphone Guide

Select the right microphone

Measurement microphones are available in many types covering various frequency ranges, dynamic ranges and application situations. The G.R.A.S. measurement microphones are amongst the world's best.

Below you can find help to select the right measurement microphone for your applications.


Externally polarized vs. prepolarized

Can you tell the difference?

All GRAS measurement microphones are of the condenser type.

This requires a polarization voltage which can either be supplied from an external power supply or the microphone itself can be polarized by injecting a permanent electrical charge into a thin PTFE layer on the microphone backplate.

Read about the externally polarized vs. prepolarized microphones


Free-field, Pressure or Random incidence

Which one should you choose?

There are three types of measurement microphones: Free-field, Pressure, and Random incidence.

You can see the differences between these three types of measurement microphones at the higher frequencies, where the size of a microphone becomes comparable with the wavelengths of the sound being measured.

Discover the difference between the three types

Dynamic range of a microphone

Which levels can the microphone handle?

The dynamic range of a microphone is defined as the range between the lowest level and the highest level which the microphone can handle.

This is not only a function of the microphone alone, but also of the preamplifier used with the microphone. The dynamic range of a microphone is, to a large extent, directly linked to its sensitivity.

Read about the dynamic ranges of the GRAS microphones


Frequency range of a microphone

Which one should you choose?

The frequency range of a microphone is defined as the interval between its upper limiting frequency and its lower limiting frequency.

With today’s microphones you can cover a frequency range starting from around 1Hz and reaching up to 140 kHz.

Learn more about the frequency range