Whether you’re browsing the internet for a vocal microphone for the stage or a condenser for your studio, it won’t be long before you’ll run into the term ‘pickup pattern’, also referred to as ‘polar pattern’. You’re also likely to bump into terms like ‘cardioid’ or ‘omnidirectional’. In this blog, I’ll present you with the pickup pattern basics, include a few field examples, and tell you what you need to know when you’re looking to, ahem, pick up a new microphone.
Which Pickup Patterns Are There?
Generally speaking, there are five types of pickup patterns: omnidirectional, unidirectional (subdivided into cardioid, supercardioid and hypercardioid) and bidirectional, also known as ‘figure-of-8’. Next up, I will briefly discuss each type and occasionally refer to the visual representation of the five patterns included a little further down the page.
For a number of pickup patterns, I’ll also refer to a specific audio fragment. The fragments can be found just below:
Figure of 8:
As you can tell, omnidirectional microphones (#1 in the image) register sound from all directions and as such, can’t be aimed in any specific direction. If you listen to the first audio fragment, you can hear an omnidirectional recording of an acoustic guitar. Some small-diaphragm condenser microphones feature an omnidirectional pickup pattern, or they might offer the possibility to swap out the capsule for one with a different pickup pattern. Certain large-diaphragm condenser mics even offer switchable pickup patterns, including an omni-mode. Lavalier and reporter microphones, on the other hand, are often omnidirectional by default, so that it doesn’t matter which direction a potential interviewee is speaking in.
Cardioid microphones (#2 in the image) only capture sound coming from the front, allowing you to keep any unwanted background noises and reflections out of the recording. This is why the cardioid pickup pattern is the most popular of the bunch, and explains why most microphones have a cardioid polar pattern, or a variation of it. In the second audio fragment, you can clearly hear how the sound coming from behind (180 degrees) is largely subdued.
Supercardioid and Hypercardioid
Just like cardioid, supercardioid and hypercardioid are also part of the unidirectional family, and often used in dynamic vocal and shotgun microphones. Simply put, supercardioid (#3 in the image) is a more-focussed version of the regular cardioid pickup pattern. Notice how in the third audio fragment, sound coming from the side (135 degrees) almost completely falls away. While some sound coming from behind (180 degrees) is registered, this pattern captures most sound from the front. Hypercardioid microphones (#4 in the image) take things even further, and in a way, suspiciously resemble their bidirectional counterparts.
Bidirectional (‘Figure of 8’)
Bidirectional (#5 in the image), better known as ‘figure of 8’, means the microphone registers an equal amount of sound from the back and the front, while any sound coming from the side (90 degrees) is almost completely shut out. This can be clearly heard in the fourth audio fragment. Ribbon microphones always have a figure-of-8 pickup pattern, but even certain large-diaphragm condensers with a switchable pickup pattern may include this pattern.
Shotgun microphones generally come with a super or hypercardioid pickup pattern, but become even more focussed thanks to the use of a so-called interference tube. Special cut-outs in this tube allow sound coming from the side to reach the capsule from different distances. These differences in distance, and therefore, time, make sure that certain frequencies (especially higher frequencies) are filtered out a little.
How Do Polar Patterns Work?
In the good ole days, there were only ‘pressure’ (omnidirectional) and ‘pressure gradient’ (figure of 8) microphones. Fortunately, it wasn’t long before someone found out that by combining both patterns, you end up with one that’s way more focussed. At the front, the positive signals of both capsules add up, effectively doubling the signal. At the back however, the polarity of a figure-of-8 capsule is negative. This, combined with the positive signal from the omnidirectional capsule, cancels out the sound picked up from behind but at the same time, gave way to the birth of the cardioid pickup pattern. Microphones with a pickup pattern selector work in much the same way and often feature two cardioid capsules facing away from each other. When both are activated, they form an omnidirectional pickup pattern. When the microphone is set to figure-of-8 mode, the polarity of the rear capsule is reversed. Any sound that then tries to reach the microphone from the side, gets subdued. Turn the rear capsule all the way off, and you’d get that trusty old cardioid pattern.
Below, I’ll give you several field examples linked to different pickup patterns. Keep in mind that these are only pointers. Every situation is different, so research, experiment and most of all, use your ears.
Choir: Omnidirectional (2x)
A choir basically forms a large sound-producing surface and generally requires two omnidirectional microphones on each side of the conductor to get a balanced audio image. If the vocalists stand at the same height as the rest of the choir instead of on a raised platform, it might be possible that the front row ‘blocks’ the rows behind it. You can solve this by setting the microphones up high so that they’re able to ‘see behind’ the first row.
Snare Drum: Cardioid
Since the differents parts of a drum kit sit really close together, snare-drum microphones tend to pick up sound produced by the hi-hat. By using a cardioid microphone with its back positioned towards the hi-hat, you can actually counter most of the crosstalk.
Live Vocals: Supercardioid
During a performance, it’s important for a vocal microphone to register as little sound from other instruments as possible. If you’re a singer in a big band, you’re best off with a supercardioid microphone. Just don’t forget to set your monitor a little to the side to ensure that it doesn’t sit right behind the microphone since, as you now know, supercardioid microphones pick up sound coming from behind.
Vocals + Guitar: Figure of 8 (2x)
If you want to record a singer-songwriter and keep the vocals and guitar parts separated as much as possible, then a little experimenting with two figure-of-8 microphones could prove well worth it. If you place the vocal microphone right up near the singer’s mouth, you won’t hear much of the guitar, since a bidirectional microphone captures barely any sound coming from above, below or the sides. By tilting the microphone upwards just a little bit, you can optimally use its blind spot. The same can be done for the microphone for the guitar, but this one needs to be tilted downwards.
Which pickup patterns do you use for and what for? Let us know by leaving a comment!