Proximity effect (audio)

The proximity effect in audio is an increase in bass or low frequency response when a sound source is close to a directional or cardioid microphone. Proximity effect is a change in the frequency response of a directional pattern microphone that results in an emphasis on lower frequencies. It is caused by the use of ports to create directional polar pickup patterns, so omni-directional microphones do not exhibit the effect (this is not necessarily true of the "omni" pattern on multipattern condenser mics, which create the "omni" pattern by summing two back-to-back cardioid capsules, which may or may not share a common backplate.)

Proximity effect can be viewed in two ways. In some settings, sound engineers may view it as undesirable, and so the type of microphone or microphone practice may be chosen in order to reduce the proximity effect. On the other hand, some microphone users seek to intentionally use the proximity effect, such as beat boxing singers in hip hop music.