The Microphone: Cardioid Polar Pattern

   By Sarah C   Categories: Audio EquipmentRecording

An important concern when recording vocals in the studio is the amount of room reverberation picked up by the microphone. Most engineers do their best to minimize it, because:

■ reverb tends to pull a vocal backwards into the mix, when the goal is often to have the singer out front;

■ a recognizable “medium cupboard” reverb character will make the production sound cheap, as well as contradicting the spatial illusion from any artificially added delay/reverb effects;

■ otherwise dynamics processing applied to the vocal will sound less natural because it’ll effectively vary the apparent level of the reverb from moment to moment;

■ pitch-correction software is more likely to misinterpret a recording with reverb.

If your singer is on-axis to the microphone, then you can reduce the level of the primarily off-axis room reflections by using a “directional” microphone whose sensitivity tails away as you move off-axis, the most common being the “cardioid” type which reaches a “null” of maximum rejection at the mic’s rear. The image below plots this directional sensitivity on a circular graph called a “polar diagram,” and you can clearly see the characteristic inverted heart shape that gives the cardioid pattern its name.

This polar diagram shows the directional pickup characteristics of an idealized cardioid microphone.

Excerpt from Recording Secrets for the Small Studio by Mike Senior © 2014 Taylor & Francis Group. All Rights Reserved.







About the Author

Mike Senior is a professional engineer who has worked with Wet Wet Wet, The Charlatans, Reef, Therapy, and Nigel Kennedy. He specialises in adapting the techniques of top producers for those working on a budget, writing regularly for Sound On Sound magazine’s ‘Mix Rescue’, ‘Session Notes’, and ‘Mix Review’ columns. He is also the author of the best-selling Focal Press book Mixing Secrets for the Small Studio.


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