What is the Proximity Effect?
The low-frequency response is boosted when the microphone gets closer to the sound sources. But you will hear the proximity effect only from a directional microphone.
The most prominent proximity effect is from a microphone with a figure-8 pattern, then a cardioid microphone, and almost no proximity effect from an omnidirectional mic. The closer you speak to either of those mics, the more noticeable this effect becomes. Your voice will become warmer, but on the other hand will be more boomy and muffled.
Real Practice of Proximity Effect
When you use microphones, especially those handheld models, you'll hear more and more bass sound, like the pops and plosives when you put the mic closer to your mouth.
You are learning some podcast skills, and if you lean into the microphone, you'll have a deep and warm radio sound.
How does the Proximity Effect Work?
The proximity effect is the result of the differences in phase and amplitude in the sound waves reaching the two sides of the diaphragm of a directional microphone. And those two variations are decided by the frequency and distance from the sound source.
First off, the phase difference, it increases with frequency. But at the same time, it is offset by damping the diaphragm 6 dB per octave to achieve a flat frequency response. Basically, that means the low frequencies still have the smallest phase difference.
So what really matters is the amplitude difference. The high frequencies arrive in parallel waves at either a large or a small distance. But the low frequencies are considered as a point source when the mics are brought close.
And because of the inverse square law, that every doubling distance away from the source results in a 6dB loss in level, the intensity of low frequencies drops off remarkably when the audio arrives at the back of the mic. Those amplitude changes cause the difference in sound pressure level of the diaphragm, which translates into a high-intensity signal.