Sound Capture - Polar pattern switch

Learning Outcomes

• Define a polar pattern and explain what a polar pattern switch changes on a microphone.
• Identify common selectable patterns: cardioid, figure of 8, omnidirectional and hyper-cardioid.
• Explain how pattern choice affects direct sound, spill, room ambience and rear/side rejection.
• Link polar pattern choices to practical recording situations such as vocals, piano, drum overheads and ensemble recording.
• Describe the relationship between directional patterns and proximity effect.
• Evaluate whether a polar pattern switch setting is suitable when shown in an exam-style equipment photo or recording scenario.

Edexcel A-Level Music Technology (9MT0) Syllabus

In Component 3: Listening and Analysing, you need to understand how music technology choices affect recorded sound. A polar pattern switch is a small control, but it can alter the whole character of a capture: how focused the recording is, how much room sound is included, how much spill is rejected, and how suitable the setup is for the task.

• Recognise that a polar pattern describes the direction from which a microphone picks up sound.
• Explain the effect of switching between cardioid, figure of 8, omnidirectional and hyper-cardioid patterns.
• Relate microphone pickup to sound capture decisions in studio and live-style contexts.
• Discuss practical consequences such as room ambience, spill, phase issues and proximity effect.
• Evaluate pattern choice when analysing equipment settings or microphone placement.
• Use accurate technical vocabulary in written answers, especially where several marks are available.
• Avoid treating the polar pattern as the same thing as microphone type; a condenser, for example, may offer several selectable patterns.

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, look more closely at that area during your revision.

1. What does a polar pattern switch alter on a microphone?
2. Which polar pattern has strong pickup at the front and rear but strong rejection at the sides?
3. Why might a cardioid setting be chosen for a vocal recording in a room with unwanted reflections?
4. What is the main advantage of an omnidirectional setting for ambient recording?
5. Which polar patterns are most associated with proximity effect?

Introduction

A polar pattern switch allows a suitable microphone, usually a multi-pattern condenser microphone, to change the directionality of its pickup. This is highly relevant to sound capture because the microphone does not simply record “the instrument”; it also records the room, spill from other instruments, reflections, and the balance between direct and ambient sound. Choosing the wrong polar pattern can make a recording muddy, distant, overly reverberant or full of unwanted sound.

In exam answers, the key is to connect the setting to its audible result. It is not enough to say “cardioid is used”; you should explain that it picks up mainly from the front, rejects much of the rear sound, captures less room ambience than an omnidirectional pattern, and is therefore often suitable for close-miking a vocal or instrument.

Key Term: Polar pattern
The directional pickup shape of a microphone, showing where it is most and least sensitive to sound.

How a polar pattern switch changes microphone behaviour

A polar pattern switch is normally found on microphones designed to offer more than one pickup pattern. Many dynamic microphones have a fixed pattern, commonly cardioid. Ribbon microphones are often naturally figure of 8. Some higher-end condenser microphones include a switch, either on the microphone body or on an external power supply, which allows the user to choose between patterns such as cardioid, figure of 8 and omnidirectional.

The switch does not change a microphone from a dynamic to a condenser, and it does not work like an EQ control. It changes the direction from which the microphone responds most strongly. This means it affects:

• how much direct sound is captured
• how much room sound or ambience is captured
• how much spill is accepted from other instruments
• whether sound from behind or the sides is rejected
• the stereo technique that can be used
• the amount of proximity effect on close sources

Key Term: Polar pattern switch
A microphone control that changes the microphone’s pickup pattern, altering its directionality and rejection characteristics.

Many polar pattern diagrams are drawn as shapes around a microphone. These diagrams represent sensitivity at different angles. A larger part of the shape means more pickup from that direction; a smaller or indented part means reduced pickup or rejection. In practice, the diagram helps an engineer decide where to place the microphone and where to position unwanted sound sources.

For example, if a singer is in the same room as an acoustic guitar, a cardioid microphone can be aimed at the singer with its less sensitive rear area facing the guitar. This will not remove the guitar completely, but it can reduce spill. If the same microphone is switched to omnidirectional, it will capture more of the surrounding room and more of the guitar, which may be unsuitable for a close vocal recording.

Test Tip: When asked to comment on a microphone setting, always link the polar pattern to the recording outcome: pickup direction, rejection, room ambience, spill and suitability for the source.

Cardioid and hyper-cardioid settings for focused capture

Cardioid is the most common polar pattern. It is named after its heart-like shape. A cardioid microphone has strong pickup from the front, reduced pickup at the sides and minimal pickup from the rear. This makes it very useful in studio and live work because it is fairly directional and helps reduce unwanted sound.

Key Term: Cardioid
A heart-shaped polar pattern with strong front pickup, reduced side pickup and strong rejection from the rear.

A cardioid setting is often a sensible choice for:

• lead vocals
• close-miked acoustic guitar
• guitar amplifier cabinets
• snare drum or toms
• piano where room sound needs controlling
• speech recording
• general studio recording in less-than-perfect rooms

Because cardioid rejects much of the rear sound, it captures less reverb than more open patterns. This can be helpful in small rooms, classrooms, practice spaces or studios with poor acoustics. If the room has flutter echo, boxy reflections or computer fan noise behind the microphone, a cardioid setting can help reduce those problems at the capture stage.

Hyper-cardioid is related to cardioid but has a narrower pickup area at the front. This gives more precise focus and greater rejection of surrounding sound, though it may have a small rear pickup lobe depending on the microphone design. It can be useful when trying to capture one instrument within an ensemble, such as a string instrument surrounded by other players, or a vocal where tighter focus is needed.

Key Term: Hyper-cardioid
A more directional version of cardioid with a narrower front pickup pattern, used when greater focus and rejection are needed.

A common exam mistake is to describe cardioid as “only picking up from the front”. In reality, it is most sensitive at the front but may still capture some side sound and a small amount of room tone. Rejection is not the same as total silence.

Exam Warning: Do not write that cardioid “blocks all sound from behind”. It reduces rear pickup, but spill and reflections may still be recorded.

A cardioid or hyper-cardioid setting is also relevant to proximity effect. Directional microphones tend to increase low-frequency pickup when placed close to the source. This can make a voice sound fuller, but it can also create a boomy or muddy recording. Male vocals and acoustic guitars can show this clearly. If a singer moves very close to a cardioid microphone, the bass response may increase; moving the microphone slightly back or using EQ can help.

Key Term: Proximity effect
The increase in low-frequency content when a directional microphone is placed close to a sound source.

Figure of 8 and omnidirectional settings for wider capture

A figure of 8 pattern picks up sound strongly from the front and rear, with excellent rejection from the sides. The shape resembles the number 8, with two main lobes of sensitivity. This pattern is found on ribbon microphones and on some selectable condenser microphones.

Key Term: Figure of 8
A polar pattern with strong front and rear pickup and strong rejection from the sides.

Figure of 8 is useful when the engineer wants controlled rejection from the sides or wants to capture two directions at once. For example:

• two singers facing each other, one on each side of the microphone
• a room sound where front and rear reflections are desirable
• mid-side stereo recording
• certain coincident stereo setups
• drum overheads where side rejection can help manage spill

The side rejection of a figure of 8 pattern can be very useful. If an unwanted source is placed at 90 degrees to the microphone, it may be reduced strongly. However, because the rear is also sensitive, anything behind the microphone will be captured clearly. This makes placement vital.

Key Term: Rear rejection
The reduction in pickup from the back of a directional microphone, especially in cardioid-type patterns.

Omnidirectional is different. “Omni” means all, so an omnidirectional microphone is intended to pick up sound equally from all directions. In practice, the microphone body may cause a slight reduction from behind, but the main idea is that the pattern is much less directional than cardioid or figure of 8.

Key Term: Omnidirectional
A polar pattern designed to pick up sound from all directions, commonly used when room ambience is desirable.

An omnidirectional setting is often used for ambient recording, especially when the acoustic space sounds good. Rather than trying to exclude the room, the engineer uses the room as part of the recording. This can suit classical ensembles, choirs, room mics for drums, or a natural piano recording in a pleasant space.

Key Term: Ambient recording
A recording approach that deliberately captures the sound of the space as well as the direct sound source.

The main risk with omnidirectional recording is that it will capture more unwanted sound. In a good concert hall, this may give a natural sense of space. In a noisy classroom, untreated rehearsal room or space with strong reflections, it may make the recording sound distant, washy or unclear. For this reason, exam answers should judge the setting in context. Omni is not “better” because it captures more; it is better only when that extra capture is useful.

Test Tip: If a question gives you a recording location, use it. An omnidirectional setting may be suitable in a good acoustic but unsuitable in a noisy or reflective room.

Figure of 8 also has strong proximity effect, often stronger than cardioid. This means close placement can add significant low-frequency weight. That may be useful on a voiceover or certain instruments, but it can also cause a thick, unclear tone. A switched figure of 8 setting should therefore make you think about both directionality and low-frequency response.

Selecting the right switch position in recording scenarios

In the exam, you may be asked to interpret a photo of a microphone, mixer or recording setup, or to evaluate settings for a particular task. A strong answer will not only identify the polar pattern but also explain whether it suits the source, the room and the recording aim.

For a lead vocal in a typical project-studio room, cardioid is often the safest setting. It focuses on the singer, rejects much of the sound behind the microphone, and captures less room ambience than omni. A pop shield may be needed, especially with condenser microphones, to reduce plosives and moisture. If the vocalist is too close, proximity effect may cause excessive bass, so distance and angle still matter.

For an acoustic guitar, cardioid can help produce a focused sound and reduce room reflections. However, if the room sounds good and a natural acoustic tone is desired, an omnidirectional setting placed at a suitable distance could capture more body and space. The choice depends on whether the production needs intimacy and separation or a more open, natural sound.

For piano, several approaches are possible. A pair of condenser microphones may be used in stereo, and cardioid settings can help focus the pickup across the instrument. In an upright piano, microphones may be placed behind the instrument facing the soundboard or on the keyboard side. If the room has many reflections, cardioid can help control the capture. If the room has a pleasing acoustic, omni might be used to include more ambience.

For drum overheads, cardioid can give a focused stereo image with less room sound. Figure of 8 may be used in some coincident or specialist configurations, including mid-side setups. The important point is that the switch position changes not only the amount of kit captured but also the balance of cymbals, room tone and spill from other instruments.

Key Term: Mid-side
A stereo microphone technique using a forward-facing mid microphone and a sideways-facing figure of 8 microphone, allowing stereo width to be adjusted later.

Stereo techniques make polar pattern choice even more significant. A coincident pair commonly uses two cardioid microphones with capsules close together at an angle. This gives a stereo image because each microphone receives a different level depending on the direction of the source, while keeping good mono compatibility because the sound reaches both capsules at almost the same time. A figure of 8 pattern is needed for the side microphone in mid-side recording, so the polar pattern switch must be set correctly.

When evaluating a polar pattern switch, ask yourself these questions:

• Is the microphone aimed correctly for the selected pattern?
• Does the pattern reject the most problematic unwanted sound?
• Is the room sound helpful or harmful?
• Is the source close enough to create proximity effect?
• Is the recording meant to be isolated or natural?
• Is the pattern suitable for the stereo technique being used?
• Would another setting give a cleaner or more appropriate result?

A typical exam-style answer might be:

Question: A condenser microphone is placed 20 cm in front of a vocalist in a reflective room. The polar pattern switch is set to omnidirectional. Evaluate this choice.

Answer:
Omnidirectional will pick up sound from all directions, so it is likely to capture a lot of room reflections as well as the voice. In a reflective room this may make the vocal sound distant or reverberant. A cardioid setting would probably be more suitable because it would focus on the singer and reduce pickup from the rear, giving a drier and more controlled vocal sound.

Another example:

Question: A microphone is set to figure of 8 for two backing singers facing each other on either side of the microphone. Is this suitable?

Answer:
Yes, this can be suitable because figure of 8 picks up from the front and rear. Each singer can perform into one side of the microphone. The strong side rejection may also help reduce unwanted sound from the sides, although the balance will depend on both singers’ distance and volume.

Notice how both answers use the same pattern: identify the setting, describe the pickup behaviour, then judge suitability.

Key Point Checklist

This article has covered the following key knowledge points:

• A polar pattern is the directional pickup shape of a microphone.
• A polar pattern switch changes the microphone’s directionality, not its basic microphone type.
• Cardioid picks up mainly from the front, less from the sides and least from the rear.
• Cardioid is useful for focused capture, reduced room sound and better control of spill.
• Hyper-cardioid has a narrower front pickup than cardioid and can give more precise focus.
• Figure of 8 picks up from the front and rear while rejecting strongly from the sides.
• Omnidirectional captures sound from all directions and is useful when room ambience is wanted.
• Directional microphones, especially figure of 8 and cardioid, can show proximity effect at close distances.
• Omnidirectional settings may sound natural in a good acoustic but messy in a poor room.
• Figure of 8 is required for the side microphone in mid-side recording.
• Exam answers should connect polar pattern settings to audible results such as ambience, spill, focus and clarity.
• Pattern choice must be judged in relation to the source, room, microphone placement and recording aim.

Key Terms and Concepts

• Polar pattern
• Polar pattern switch
• Cardioid
• Hyper-cardioid
• Proximity effect
• Figure of 8
• Rear rejection
• Omnidirectional
• Ambient recording
• Mid-side