Proximity Effect
Definition
A bass boost that occurs naturally when a directional microphone (cardioid, figure-8) is placed very close to a sound source — typically within 15 cm. The closer the source, the more pronounced the low-frequency emphasis. Omnidirectional microphones do not exhibit proximity effect.
In Simple Terms
The closer you get to a directional microphone, the more bass it picks up. Singers who eat the mic get a boomy, warm sound; step back and it thins out. Radio DJs and podcasters use this on purpose for that deep, intimate voice sound.
In Practice
A vocalist recording at 5 cm from a cardioid condenser exhibits significant low-frequency buildup below 200 Hz. Moving to 20 cm reduces this proximity-induced bass boost while maintaining the natural tone of the voice. The engineer uses a high-pass filter to compensate when close placement is preferred.
Common Confusion
Proximity effect is not exclusive to vocals — it applies to any directional microphone close to any source. A guitar amp mic'd at 2 cm from the cone exhibits the same low-end buildup. The reason vocals feel like the canonical case is that singers move while performing, modulating proximity effect dynamically — guitar amps don't.
Sources & Verification
- Eargle, J. — The Microphone Book (2nd ed., directional microphone behavior)Focal Press, 2004
- Bartlett, B. — Practical Recording Techniques (7th ed.)Routledge, 2016
Last verified: 2026-05-05