X-Y Techniques for Hypercardiods & Cardioids

The most commonly used technique is the x-y cardioid and hypercardioid. The microphone pair can be setup with an included angle between 60 and 120 degrees. The angle will determine the apparent width of the stereo image, the amount of reverberant sound and the bass response. The wider the angle the more natural the soundfield up to the point where the angle becomes too great and a hole appears in the center. 90 degrees provides good results with any cardioid or hypercardioid microphone.

X-Y Techniques for Hypercardiods

Hypercardioids require a smaller included angle than cardioids in order to prevent a hole from occurring in the middle of the soundstage. Typically a hypercardioid will be used with an included angle of between 60 and 100 degrees. We have found that at 70 degrees and smaller the soundstage becomes distorted and somewhat triangular. Using more than 90 degrees with a hypercardioid can be tricky and not all hypercardioids are suited to this. Hypercardioid microphones are best suited to indoor recording as they do a good job at rejecting building acoustics while still producing a credible soundstage. Their increased "reach" allows for more distance from the sound source while maintaining a good direct to reverberant sound ratio. They also have a small reverse polarity lobe which offers a good midpoint between the classic Blumlien and X-Y cardioid techniques. Their weakness is that they tend towards brightness and often exhibit weak bass response and significant bass coloration.

X-Y Techniques for Cardioids

Cardioid microphones are typically used with an included angle of 80 to 120 degrees. The Cardioid pickup pattern is wider than the hypercardioid and has no rear lobe ,therefore, it has maximum rejection at 180 degrees. It is best suited to better acoustic environments than the hypercardioid due to the larger "area of space" it pickups. When used in poor acoustic settings the direct to reverberant sound ratio suffers.

It is common to aim the axis of the microphone at the outside edges of the sound source to minimize this effect. The use of hypercardioids would yield better results as the larger included angle offers a more natural sense of space. When the included angle of a pair of cardioid microphones drops below 80 degrees the mono summing of the information common to both collapses the soundstage. The cardioid mic pair also produces a more "distant" perspective than the hypercardioid.

When used outdoors the cardioid is clearly superior to the hypercardioid. They have a more open, natural sound with a better sense of depth than the hypercardioid. In the outdoor setting, we are not as concerned with reflected sound as there are far fewer of these in a minimal structure. The sub-cardioid pickup pattern, which is even wider in its off axis response, is the best choice in a directional microphone for outdoor use.