Proximity effect is an acoustic phenomenon that occurs when a sound source gets very close to a microphone. It causes an exaggeration or boost in the lower frequencies, especially bass tones. There are a few key aspects about proximity effect that live sound engineers need to understand:
- It is most pronounced when using directional microphones like cardioid or figure-8. Omnidirectional mics do not exhibit proximity effect.
- The boost in low frequencies starts happening around 1-3 inches from the mic and gets more exaggerated the closer the source gets. Direct contact can cause huge bass boosts.
- Vocals get boomy and muddy sounding when too close due to proximity effect. Instruments also lose definition.
- Proximity effect can be desired on sources like kick drum and electric guitar cabinets to fatten up the sound. But it also makes mixing harder.
- Engineers can compensate with EQ cuts in the bass and lower midrange areas. But it’s often better to back mics away to the 3-12 inch “sweet spot”.
- Mixing is easier when mics are at a consistent distance based on the proximity effect curve of the mic.
- Some microphone models are designed to have less pronounced proximity boosts. These include small and large diaphragm condensers.
- Proximity effect also occurs, but to a lesser extent, with figure-8 mics in the null points of the pickup pattern.
So in summary, proximity effect is an important phenomenon for live engineers to control through proper mic placement and mixing techniques. Understanding how a given microphone model responds to close sources is crucial.