Understanding Microphone Pickup Patterns: omnidirectional, bidirectional, cardioid, supercardioid, and hypercardioid

Choosing the right microphone for your recording or performance setup is just as crucial as understanding how it will capture sound. One key aspect of a microphone's capabilities is its pickup pattern. This term refers to the range and direction in which a microphone is most sensitive to sound. Understanding these pickup patterns can significantly enhance your ability to capture audio clearly and effectively. In this article, we'll explore the different types of pickup patterns and their applications.

Introduction to Microphone Pickup Patterns

Microphones come in various forms, each with a unique pickup pattern. These patterns range from omnidirectional, which captures sound equally from all directions, to hypercardioid, which focuses on capturing sound primarily in front while rejecting sound from the rear.

Omnidirectional Pattern

The omnidirectional microphone is at one end of the spectrum. It captures sound from all directions equally, making it ideal for situations where a full 360-degree sound capture is desired. Examples of omnidirectional microphones include ribbon microphones and condenser mics without any pattern selection switch.

Bidirectional (Figure of Eight) Pattern

The bidirectional or figure-of-eight microphone captures sound from both front and back, but rejects signals from the sides. This pattern is commonly used in setups where sound sources are placed symmetrically, such as in the Voight-Kampff test scene from Blade Runner, where the interviewers are on either side of the microphone.

Cardioid Pattern

The cardioid pattern, resembling a heart shape, is perhaps the most widely used pickup pattern among directional microphones. It's primarily sensitive to sound coming from the front and rejects sound from the rear. This makes cardioid microphones ideal for live performances, where they can reduce background noise while clearly capturing the vocalist or instrument.

Supercardioid and Hypercardioid Patterns

Supercardioid and hypercardioid microphones are narrower than cardioid microphones, offering more focused directivity. Super- or hypercardioid microphones capture sound primarily from the front and reject it from the sides and rear more effectively than cardioid microphones. These are excellent for capturing a precise sound source, such as a drum or a guitar, in a studio setting.

Directionality and Frequency Response

The sensitivity of a microphone to sound from different angles is known as its directionality. Even within the same pickup pattern, the microphone's sensitivity to different frequencies can vary. For instance, high frequencies tend to be attenuated more when off-axis, while low frequencies can still be heard effectively. This is why manufacturers often provide detailed frequency response charts that show how the mic's sensitivity changes with angle and frequency.

For a typical microphone, the pickup pattern graphic is a simplified view, often showing only the mid-range response. However, the full frequency response can be complex, especially in more precise mics. Generally, as you move off-axis, high frequencies begin to drop off before low frequencies, reflecting the directional nature of the microphone.

Conclusion

Understanding the pickup patterns of microphones is essential for effective sound recording and performance. Each pattern offers unique benefits, ranging from a 360-degree capture with omnidirectional mics to precise single-source capture with supercardioid and hypercardioid mics. By knowing how these patterns work, you can select the right microphone to achieve the best sound in any given scenario.

Further Reading

For in-depth information on frequency response, see the Guide to Frequency Response in Microphones.