Proximity Effect

An increase in bass or low frequency response when a sound source is close to a cardioid or bi-directional (figure 8) microphone. Proximity effect is an exaggeration of low frequencies caused by the use of ports to create directional polar pickup patterns, so omni-directional mics are not affected. Depending on the mic design, proximity effect may easily result in a boost of up to 16dB, usually below 100Hz. Proximity effect increases as you get closer to the microphone, so the bass boost will vary depending on your distance from the mic. Vocalists tend to like proximity effect since it fattens up their voice, but a constantly varying bass boost can wreak havoc on headroom and carefully set levels! Obviously, if a vocalist is “eating the mic” to get proximity effect, the Inverse Square Law (WFTD 6/12) tells us that the levels the mic sees are increasing dramatically as well — distortion can easily result, from either mic diaphragm breakup or electronic overload. (You may occasionally see proximity effect referred to as “bass tip-up.”)