Microphone polar patterns explained: Subcardioid

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Directionality is the sensitivity of a microphone to sound, relative to the angle or direction from where the sound is coming from. Several directional patterns are available, and these are represented in graphs and are called polar patterns. The graph of a polar pattern shows the change in sensitivity 360-degrees around the microphone. This is as long as the microphone lies at the centre and the 0-degree point is in the front.

There are quite a several microphone polar patterns. these are the unidirectional, omnidirectional, and bi-directional, cardioid, hypercardioid, subcardioid polar patterns, etc. So, in this post, we are going to be looking at the subcardioid polar pattern.

What is a subcardioid polar pattern?

The subcardioid polar pattern is another variant of the cardioid polar pattern. In application, it looks like it is a cross between the omnidirectional and cardioid polar patterns. The subcardioid polar pattern is best suited to the picking up of a sound source that moves a lot while still in front of the microphone.

Sometimes called the “wide cardioid”, the subcardioid is an obscure polar pattern. Its directionality is somewhat close to Omni, but not entirely, which gives a very natural and open sound that is suitable for low stage volume performance where a more organic sound is desired. This subcardioid polar pattern is also less sensitive to the proximity effect. This is especially true when it is in combination with a dual diaphragm. However, they are more prone to feedback. When considering subcardioids, think small acoustic low volume gigs.

As earlier stated, the subcardioid or the “wide cardioid” polar pattern is a less famous relative of the famous cardioid pattern. Knowing this pattern of microphones, as well as it’s pros and cons will surely help you choose and understand the right microphones to use, whether you are a professional or an amateur.

What can I use a subcardioid microphone for?

Since the subcardioid pattern is quite an uncommon microphone pattern, it will likely not be chosen for many applications by users. However, there are some cases where the use of a subcardioid polar pattern microphone does make sense.

Best Applications for Subcardioid Microphones

The subcardioid pattern may be useful in any situation where a more directional microphone is required.

  • useful to capture a sound source as well as the sound of the acoustic environment.
  • better used in an application where lesser proximity effect is desired, for single-source isobooths.
  • for individual isobooth sources to reduce vocal plosive risks.
  • can be used for a natural pickup with a certain directionality.
  • to naturally pick up sounds at the front while rejecting sounds at the rear.

And of course, with those in mind, there are some pros and cons of using the subcardioid microphones:

Pros of using the subcardioid microphones

  • Subcardioid microphones are a popular choice for live close-ups, movies, and noisy environments.
  • When the need for close-miking arises, you may use a subcardioid microphone. It focuses on what is pointed at it. For that, it is an excellent option for anyone who wants to record instruments in close proximity, or when you are attempting to isolate a particular source of sound in a noisy environment.

It is pertinent to note that the rear sensitivity lobe makes the placement of the microphones essential for isolating sound sources with subcardioid microphones.

  • Null points lie at 127° and 233°

The ideal subcardioid polar pattern characteristically has null points of sensitivity at around 127° on both sides of its on-axis (i.e. 127° and 233°). The null points represent the directions in which the microphone theoretically does not pick up any sound. This means that the sound will be greatly attenuated (especially if at high frequencies). The nature of the sound, reflections, and acoustics allows the sounds to enter the microphone from other directions, even if it comes directly from a null point direction.

  • Rear cone of silence

With the null points at 127° and 233°, we have known the angles of maximum rejection of the sound of a 2D subcardioid microphone. In 3D, this means a rear “cone of silence”.
Understanding this cone of silence will help a great deal in the proper positioning of a subcardioid microphone because microphones operate in a 3D space.

  • Rear sensitivity lobe yields -10 dB at 180°

The ideal rear lobe of a subcardioid is remarkable, but it is generally not excessively present in the microphone signal at -10dB compared to the sensitivity on-axis. Better positioning of a subcardioid microphone can be made with the knowledge of the rear lobe of the subcardioid pattern. At 10dB the rear lobe has less sensitivity than the on-axis response.

Cons of using the subcardioid microphones

  • You may get undesired results if you use it in live performances, in front of foldback monitors.
  • It is not suitable for moving targets, because it is a stationary microphone.
  • It may not be suitable to record the ambiance of a natural room.
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