What is a Cardioid Microphone?

What is a Cardioid Microphone

The cardioid microphone is one of the most used, widely preferred options for studio recordings, broadcasting, and live performances.

Cardioid microphones get their name from the Latin term meaning heart shape, representing the shape of their polar response graph. These heart-shaped polar patterns are also referred to as kidney and unidirectional. 

This article will walk through microphones in general and discuss cardioid microphones in depth. 

Table of Contents

Types of Microphones

A microphone is an electronic appliance that converts sound energy to electrical energy. Markets today are flooded with many varieties of microphones, thoughtfully designed to cater to a variety of needs. Let us begin our discussion by looking at the different types of microphones

Dynamic Microphones

Dynamic microphones are versatile and are used for all sorts of audio in studios. For example, one can spot dynamic microphones on guitar amps and snare drums. Our write-up on what is a dynamic microphone is a more in-depth guide. They tend to be the most affordable among all categories of microphones. Dynamic microphones tend to add warmth to sound and can generally handle high sound pressure levels.

Condenser Microphones

The first condenser microphone was invented in 1916. Since the transient response of condenser microphones is outstanding, they can capture the sound of a musical instrument accurately.

Condenser microphones are intended for soft sounds. They can be spotted in use in studios. Compared with their dynamic siblings, they are usually significantly more expensive. We have a worthy read on what is a condenser microphone which goes into more detail.

Condenser microphones offer more polar patterns than dynamic microphones. They can be divided into three categories based on their diaphragm sizes. 

First, let us understand the role diaphragms play in microphones. 

The Role of Diaphragms in Microphones

Microphones pick up their sound through a diaphragm. The diaphragm is a thin material that exhibits vibration when it comes in contact with sound. Here, we discuss three different sizes of diaphragms and how they differ.

Small Diaphragm

Microphones with small diaphragms have a thin, cylindrical shape. They are light, making them easy to position and reposition. However, microphones with small diaphragms exhibit low sensitivity and increased internal noise. 

Medium Diaphragm

Microphones with medium size diaphragms combine certain features of both small and large-diaphragm microphones. Akin to small diaphragms, they retain high-frequency content. On the other hand, similar to large diaphragms, microphones with medium diaphragms catch warm sounds. 

Large Diaphragm

Due to their size, large diaphragms exhibit even more freedom of movement and hence, pick up even the slightest of sounds. As a result, large-diaphragm condenser microphones capture low sounds and are not very good at capturing highs. Owing to this attribute, large-diaphragm microphones may distort sound when sound pressure level is high. 

Condenser Microphone

Ribbon Microphones 

Ribbon microphones are always bidirectional. They are used for softer sounds and need to be handled with utmost care. Unfortunately, they tend to be very expensive and are fragile. For further reading, we have written a complete guide to what is a ribbon microphone. The Royer R-121 is a popular ribbon mic. 

Let us now look into polar patterns and their importance in the world of microphones. 

Polar Patterns and Microphones

What are polar patterns? 

Polar patterns refer to the response of any microphone to sounds arriving from different directions. These patterns help in comprehending the sensitivity of sounds from various directions. Polar patterns are documented in the form of a 2D graph for better understanding. 

The three most common polar pickup pattern types are unidirectional, bidirectional, and omnidirectional.

Can polar patterns affect the sound  of a microphone?

Yes, polar patterns can affect the sound in microphones, since different polar patterns result in different frequency responses.  

How do I read a polar pattern diagram?

As we will be using the terms polar pattern and pickup pattern several times in this article, I feel it necessary to give the reader a brief overview of how a polar pattern diagram is interpreted. A polar pattern diagram is a 2D representation of how a microphone responds to the sonic energy in its surroundings. Imagine everything in 3D to better understand the directionality of different microphones, as you know the following lines. The circles represent 360 degrees and are labeled clockwise. The concentric circles on the inside refer to the sensitivity of sound, which

is expressed in decibels. You can now see and analyze the polar pattern diagrams for different microphones. 

The solid portion or shape on the graph indicates all the directions from where a given microphone can capture sound. On the other hand, the voids or empty parts signify that the microphone does not capture sound from those directions. 

This directionality of sound is harnessed to attain clean, isolated sound and successfully cancel all background noise. 

How does a cardioid microphone work?

Now that we have looked into polar patterns, let us understand the functioning of a cardioid microphone from its polar pattern response graph. The polar pattern diagram of cardioids is heart-shaped. If you imagine this shape in 3D, it will look similar to an apple.

0 degrees

The polar pattern is the most sensitive at 0 degrees. 

90 and 270 degrees

The cardioid polar pattern is half as sensitive to the sides. 

Null point

As the name implies, the null point is the point where no sensitivity is observed. A null point is precisely the mirror image of the direction it is pointing to at 180 degrees. The cardioid microphone’s rear rejection allows for easy positioning of cardioid mics. 

This characteristic ensures that only the sound to which the microphone faces gets picked up. Conversely, putting the microphone away from the sound source you do not wish to pick up will ensure that a particular sound doesn’t get picked. 

As a result, the sound quality in cardioid microphones is clear, clean, and isolated from unnecessary background noise. 

Cardioid microphones have a unidirectional pickup pattern. The term unidirectional implies that they are sensitive to sound coming from one particular direction. Cardiac microphones are capable of detecting on-axis sounds.  

How did Cardioid Microphones come into existence? 

Cardioid mics came into existence when audio engineers fused figure-8 and omnidirectional signals. Today, they are the most common unidirectional microphones. They have been developed and improved to the extent that it is often said that a cardioid doesn’t just hear; it listens! Continue reading ahead, and you will understand this better.

Omnidirectional Microphones

Omnidirectional microphones pick up gain from all sounds in all directions. The use of omnidirectional microphones is hence desirable in situations where capturing noise from all directions is desirable. Yes, this means that even if you speak into the microphone from the side or behind, it will still capture the noise. 

Bidirectional or Figure-8 Microphones 

Figure-8 microphones are named after their polar response pattern, which resembles the number 8. At 0 degrees and 180 degrees, figure-8 microphones have the same sensitivity. T 90-degree and 270-degree angles have the least amount of sensitivity. Sometimes, they are also referred to as figure-of-eight microphones. Figure-eight implies a bi-directional pickup pattern, which is sensitive to sound coming from only the front and back. The sound coming from the sides won’t be captured by figure-8 microphones because they detect pressure differences. This is done by measuring the pressure difference between each side of the open diaphragm. These microphones have a minor bass response. However, they are susceptible to wind sounds and other background noises.

Figure 8 microphones are somewhat rare these days. However, manufacturers such as Neumann do make them.

Where are figure-8 microphones ideally used? 

Recording studios may capture multiple artists and instrumental sounds simultaneously. Despite all the sounds playing simultaneously in a space, you can still capture clean sound with figure 8 microphones. 

The birth of Cardioid Microphones 

To develop the cardioid microphone, engineers combined omnidirectional patterns with bidirectional patterns. 

Multi-pattern Microphones 

Multi-pattern microphones were developed after cardioid microphones and are designed for even more specific sound isolation.

Supercardioid Microphones 

Supercardioid mics can be sensitive to sounds that are directly behind the mic. Supercardioids require the user to maintain the same distance from the mic at all times to attain the best possible results. These microphones are best suited for live performances since they allow for very high gain before feedback. We have written the article titled what is a Supercardioid microphone, which goes further in depth.

Hypercardioid Microphones 

Where considerable isolation is needed between sound sources, you can spot hypercardioid devices at work. Hypercardioid microphones are more sensitive to sounds coming from the rear. As a result, they provide extreme rejection of ambient sound sources. Because of this back rejection, one might have to reposition stage monitors and other instruments from time to time. In addition, hypercardioid microphones are used for recording instrumentals. Recommended reading: What is a hypercardioid microphone?

Are hypercardioid and supercardioid the same? 

Hypercardioid and supercardioid microphones are very similar, but the former offers a narrower picking pattern relative to the latter.

What is the difference between cardioid and supercardioid?

Cardioid microphones are less directional than supercardioid microphones. Supercardioid microphones, on the other hand, have high directionality. 

Wide Cardioid Microphones

The subcardioid microphone or wide cardioid microphone has no null points at all. It is produced with about a 7:3 ratio with a 3-10 dB level between the rear and front pickup. Wide cardioid or subcardioid microphones are a fusion of omnidirectional (What is an Omnidirectional microphone) and cardioid microphones. Hence, they have the advantages of both. For example, podcasts or studio recordings that need little of the proximity effect are covered with these microphones. 

Subcardioids are unidirectional while they also pick up sounds from other directions with less amplitude. This characteristic enables the recordings to turn out more realistic with desirable warmth in the sound. Wide cardioid mics are also preferred for recording multiple instruments.  

Shotgun Microphones

Shotgun is also a variation of conventional cardioid microphones. They are called shotgun microphones due to their thin, long appearance.

These microphones pick up sound in high quality, even from considerable distances. Shotguns can be spotted in use on TV sets, broadcasting events. It is conventional to use a shotgun to shoot scenes where dialogue is recorded while ensuring no microphones can be seen. 

A scene can be shot with shotgun microphones placed at a certain distance away from the camera. Azden’s SGM-20 is one such microphone. 

The Cardioid family of microphones 

What is noteworthy about all microphones with the cardioid suffix is that they have their primary sensitivity in front of the microphone. It is incredible how sound engineers have designed so many different options and variations of cardioid microphones. One is likely to find the microphone that meets their needs among the available cardioid microphones. 

Microphones and the Proximity Effect connection

What is the proximity effect?

The proximity effect is a phenomenon that leads to an increase in low-frequency response as the microphone is moved closer to the source. Generally, frequencies below 200 Hz are considered low frequencies.. 

The Proximity Effect in Microphones 

The amount of proximity effect differs from microphone to microphone. The pickup pattern of a microphone is responsible for the same. The highest proximity effect is observed in figure-8 microphones and the lowest in cardioid microphones. On the other hand, omnidirectional microphones do not exhibit the proximity effect at all.

Where is a cardioid microphone used? 

Rear rejection and unidirectionality make cardioid microphones ideal for use in broadcasting, studios, and stage. 

Live concert 

In a live concert, there will be musical instruments playing in the foreground, the audience in the front, and the performing artist. In this case, it would be ideal to eliminate all background noises so that a microphone captures the artist’s voice solely. Cardioid microphones are useful in this situation since they prevent leakage of sound from one instrument into another. 


With cardioid microphones, miking drums is very convenient and produces high quality results post-production. 

Miking One Source at a Time

Cardioid mics are placed such that they point away from stage monitors. The cardioid mic here is pointing towards the singer. Hence, the singer can be spotted singing into the mic, which ensures the singer’s noise gets registered while noise from the monitor doesn’t get registered. 

Spaces with poor acoustics

Miking with cardioids at close proximity can work wonders in untreated rooms. In addition, cardioid microphones can minimize the reflected sound and are therefore appropriate for rooms with poor acoustics. If you are a beginner with limited funds, a good secondhand cardioid from a reliable brand would be a good investment. 

Other instances of miking single sources are miking instruments in music performances to end up with multiple individual sounds, all of which are clear and premium quality.

This will help an individual’s voice turn out crystal clear and disturbance-free even with significant background noise.

microphone and computer screen

Microphones and their Frequency Responses

To better understand how a cardioid microphone works, let us also look at the cardioid microphone’s response to change in frequencies. 

A microphone’s frequency response is a microphone’s response to a given frequency. Sonic energy reaches the microphone in the form of sound waves. As sound energy is converted to electrical energy by the microphone, audio signals are produced. 

These audio signals are in the frequency range of 20 to 20,000 Hz. Therefore, frequency response is the particular range of a specific microphone that lies among these frequency values. 

Cardioid mic’s response to higher frequencies

Cardioid microphones generally become more directional at higher frequencies. 

Cardioid mic’s response to lower frequencies

On the other hand, in response to lower frequencies, cardioid microphones lose their rear null point and exhibit changes in their cardioid polar pattern. 

Cardioid Microphone vs. Omnidirectional Microphone

Understanding microphones becomes a lot easier when we compare the characteristics and features of the two. So let us look at cardioid microphones and omnidirectional microphones to understand both of them better. 

Capturing Sound

Cardioid microphones capture sound only from the front and do not register sound from the rear. On the other hand, omnidirectional microphones are likely to capture almost every sound around them and cancel out nothing. 

Capturing group performances

Have you seen a group of performers standing in an arch-shaped formation with only one microphone in the middle? Now that you know enough about cardioid microphones, you can comprehend what is likely to happen in such a situation if the microphone is cardioid. The microphone will register the voice of only the performer in the middle standing right in front of it. Hence, in situations where capturing group performances regularly is a necessity, an omnidirectional microphone would be a better buy. 

Utilizing all sounds for a natural effect 

For some recordings, artists might desire a more natural effect. This natural effect does not come from isolated sound but by preserving natural characteristics such as reflections. These add to the overall ambiance and natural character of the sounds. Here, the use of omnidirectional microphones becomes imperative. Conversely, cardioid microphones are meant to isolate sound, and they won’t capture further minute details in the foreground that might sometimes be desirable. 

Proximity effect

Avoiding proximity effects is possible in omnidirectional microphones. However, doing the same in cardioid microphones may not always be possible.  

Why should you use a cardioid microphone?

The two most important traits of cardioid microphones are rear rejection and unidirectionality. These attributes make cardioid microphones suitable for broadcasting, stage performances, and other settings where noise isolation is crucial.

What are the advantages of cardioid microphones?

Noise reduction and feedback suppression 

The cardioid microphone’s front focused pattern helps suppress feedback and isolate unwanted noise. This quality of cardioid microphones makes their use suitable for concerts, live performances, recording podcasts, and karaokes. 

More Rear Rejection

Cardioid microphones have better rear rejection than hypercardioid and supercardioid microphones. 

Variety in the Cardioid Microphone Market 

Cardioid microphones have been around for quite a while now. Technology has advanced to the point where you will find countless cardioid microphones in the market. As a result, you will see a variety of prices, aesthetics, sound quality, wireless connectivity, and practically anything else the user might desire. 

What are the disadvantages of cardioid microphones?  

Proximity effect

The low bass frequencies when capturing sound will increase when the microphone is brought closer to the source.

microphone mounted on mic holder

Which are the best cardioid microphones? 

Here is our list of some of the best cardioid microphones available. 

Shure SM58

Shure is one of the most renowned names in the world of music, and their SM58 mic has been around for a while.

Why should I invest in a Shure SM58?

Robust and Durable

Shure SM58 is very well built so that you need not worry about its durability.

Voice quality

The microphone is designed so that its built-in pop filter and spherical mesh grille prevent it from registering the wind noises.

Handles High Sound Pressure Levels 

It can take a good deal of sound pressure and can for all sorts of instruments, from drums to guitars. 

Value for Money

The Shure SM58 is value-for-money for the quality it offers. The microphone originally retails for $149. However, you can often find it for $120 or so during discount offers and the sale periods. 

What are the disadvantages of Shure SM58? 

The microphone does not come with a boom mic stand, and it comes with a standard microphone stand. 

Audio-Technica AT2020

The AT2020 is preferred for smaller studios and live recordings. This offering by Audio-Technica has a comprehensive frequency response and low noise pickup. 

What makes the Audio-Technica AT2020 worth buying?

Handles High Sound Pressure Levels

One can use the Audio-Technica AT2020 for recording string instruments, vocals, and a Leslie amp too. 

Noise Isolation

Cardioid microphones and superb noise isolation go hand in hand. The same applies to Audio-Technica AT2020. Its noise isolation trait helps in recording vocals and sounds clean and clear. If you are in the music industry or happen to be a music enthusiast, you might have come across artists expressing how they wish to have a certain ‘warmth’ in recordings. The Audio-Technica AT2020 gets a thumbs up in this particular requirement. 


The microphone weighs 0.76 lbs and has an aesthetically appealing design. 

What are the disadvantages of Audio-Technica AT2020? 

Pop Filter Not Included 

You might want to get hands-on with an external shield or pop filter because the microphone can pick even the slightest extraneous sounds, such as from wind. However, you can always order from customized bundles where sellers have already grouped accessories to be used with a product in one package. For example, an Audio Technica AT 2020 bundle may comprise a boom arm, a pop filter, and XLR cables, along with the microphone itself. 

Neumann TLM 103

TLM 103 is easily TLM’s most successful and beloved product. The capsule design is derived from Neumann’s legendary U87A. 

What are the advantages of Neumann TLM 103?

Handles High Sound Pressure Levels

The TLM 103 can handle sound pressure levels of up to 138 decibels. Along with this, it can handle the slightest whispers (7 dBA) too. Because of its large diaphragm, the Neumann TLM 103 can take anything from whispered dialogue to the most potent bass instruments. The number of positive reviews and the market presence of this product testify that all the claims the company makes are valid. 

Sound quality

The Neumann TLM 103 offers superior quality balanced sound with enhanced presence. It is also used in classical recordings where cello and double bass need to be recorded. 

What are the drawbacks of Neumann TLM 103?

Price point 

The Neumann TLM 103 is priced above 1000 dollars, making it a tough price point to justify for beginners.

Sennheiser MD 421-II

The Sennheiser MD 421-II is also a top name among the world’s best microphones. Let us see what makes it worth buying. 

Is the Sennheiser MD 421-II a good buy?

Handles High Sound Pressure Levels

The Sennheiser MD 421-II can cope with high sound pressure due to its large diaphragm and dynamic element. Its dynamic capsule allows it to handle nearby signal responses and high SPL (Sound Pressure Levels). 


Sennheiser’s MD 421-II is a rugged, professional microphone. The device weighs just 200 grams and is both dust and humidity-resistant. Sturdy and lightweight, this product has a good feel to it.

Five-Position Bass Roll-off

The five-position roll-off switch provides the user with flexible bass attenuation. The ability to conveniently change bass allows the use of the Sennheiser MD 421-II in various situations. 

What are the drawbacks of the Sennheiser MD 421-II?

Microphone clip design

The microphone’s clip design may not be convenient for everyone. As a result, it has mixed reviews; some love it, while some are concerned they might damage the microphone. 

Choosing the Right Microphone 

Here are some important elements and features to consider when looking for the right microphone for yourself. 

Frequency Response Range

It is important to compare and analyze the frequency response range of each microphone you are considering purchasing. For example, the frequency response range for a vocal microphone should look something like 80 Hz to 15 kHz. However, for a microphone to be used with a bass drum, the minimum frequency can be around 30 Hz.

The Microphone’s Directionality

Determine your desirable directionality for your use case. You can then search for microphones that support it.

Price Point 

Microphones are available from $100 to beyond $1000. Understand that expensive does not always mean better. Read reviews and try to test microphones with your voice. You can also opt for second hand microphones. It would be best to keep in mind that you might need to buy additional supplementary accessories such as a pop filter, cables, and more. Our article on How much microphones cost may be a useful read after this.


Look for a robust microphone that is built to quality materials. Many microphones these days are built well, and a well-built microphone will last you a long time.

Discuss with acquaintances in the music space

If you have a musician friend, do not hesitate to reach out to them. They can help you with some shopping advice that you may not have considered prior. 

Experiment and see what works best for you 

For music lovers and those who record podcasts and albums, you would want to know why cardioid microphones are so great. Using various instruments, you can observe the differences by recording multiple devices with different polar patterns in various setups. From my personal experience, I can tell you condenser microphones are good for home studio recordings. You will also be able to find the setup and microphone combination that works best for you in this way. However, there are no rules. You chose what works for you. Try different permutations and combinations until you achieve your desired sound quality. Some people may want a balanced sound; some might be looking for natural effect and warmth; requirements are bound to vary. 

Which type of microphone is best for singing?

Singing without a microphone and with a microphone is not the same. The bass tends to rise as the distance between the performer and the microphone decreases because the proximity effect springs into action. Differences in tonal balance may surface if you constantly change the distance between yourself and the microphone while performing. A seasoned performer may already have a good idea of these intricacies and can handle these situations. 

How to take care of microphones?

Here are some basic tips for taking care of your microphones. 

Screen pop filter

Put a pop filter over your microphone when recording vocals. Not only will this prevent extraneous noises, it will also prevent saliva from accumulating inside the device. 

Cover the microphone when not in use

Not all microphones are dust and moisture resistant. Thus, keep your microphones wrapped securely in the product cover or plastic to prevent dust particles from building on and inside the microphone.

Parting Words

Now that we have reached the end, let us know in the comments section below if you managed to find answers to your queries on cardioid microphones. If you liked what you read, share this article with your friends and peers too.

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