Microphone Basics: Frequency Response
In our last posts we discussed the basic microphone caracteristics: Transducer Types and the Polar Pattern. In this post we will explain more about the third most important characteristic: Frequency Response.
The frequency response is the output level or sensitivity of a microphone over its operating range from lowest to highest frequencies. Virtually all microphone manufacturers list the frequency response of their microphones over a range, for example 50 – 15,000 Hz. This usually corresponds with a graph that indicates output level relative to frequency. The graph has frequency in Hertz (Hz) on the x-axis and relative response in decibels (dB) on the y-axis.
Flat frequency response
All audible frequencies (20 Hz – 20 kHz) have the same output level. This is most suitable for applications where the sound source has to be reproduced without changing or “coloring” the original sound, e.g. for recording.
Tailored frequency response
A tailored response is usually designed to enhance a sound source in a particular application. For instance, a microphone may have a peak in the 2 – 8 kHz range to increase intelligibility for live vocals. A microphone may also be designed to be less sensitive to certain other frequencies. One example is reduced low frequency response (low end roll-off) to minimize unwanted “boominess” or stage rumble.