If you’ve spent any time shopping for a podcast microphone, you’ve probably seen the word cardioid. It appears everywhere.
A microphone might be described as a “dynamic cardioid microphone” or a “condenser microphone with a cardioid polar pattern.” That sounds technical, but the basic idea is surprisingly simple.
A cardioid microphone is designed to pick up sound mainly from the front while being less sensitive to sound coming from the sides and especially the rear.
That’s one reason cardioid microphones are so popular for podcasting, streaming, vocals, voiceovers, and home recording.
But what exactly does cardioid mean? And why might you want this pattern instead of an omnidirectional or bidirectional microphone?
Let’s break it down.
What Is a Cardioid Polar Pattern?
A cardioid polar pattern describes the directions from which a microphone is most and least sensitive to sound. A cardioid microphone primarily captures sound coming from the front.
It captures less sound from the sides and typically has its strongest rejection toward the rear. Imagine you’re sitting at your desk recording a podcast. You’re directly in front of the microphone. Your computer is behind the microphone. There’s also a window somewhere to the side.
A cardioid microphone is designed to concentrate more heavily on your voice while reducing sounds arriving from less sensitive directions.
It won’t completely remove your computer fan or traffic outside. But microphone direction can help you produce a cleaner recording.
Why Is It Called Cardioid?
The name comes from the shape of the microphone’s polar diagram. Microphone manufacturers use diagrams to show how sensitive a microphone is to sounds arriving from different angles.
If you look at the diagram for a cardioid microphone, the pickup area looks somewhat like a heart.
The word “cardioid” comes from the idea of a heart-shaped curve. You don’t need to understand the mathematics behind the shape to use the microphone.
Just remember:
Front = strongest pickup
Sides = reduced pickup
Rear = strongest rejection
The exact response varies between microphones and frequencies, but that’s the general idea.
Why Is Cardioid So Popular?
Most of the time, you don’t want your microphone to record everything in the room equally. You want it to hear something specific. For a podcaster, that’s usually your voice. For a singer, it’s the vocal performance. For a streamer, it’s the person sitting at the computer.
For someone recording an acoustic guitar, it’s the instrument. A directional pattern gives you more control over what reaches the recording. That’s particularly useful when your room isn’t perfect.
Most people don’t have a professionally treated recording studio at home. They have bedrooms, offices, living rooms, and spare rooms.
A cardioid microphone can help you concentrate more strongly on the sound you actually want.
How Does a Cardioid Microphone Pick Up Sound?
Imagine the microphone sitting in the middle of a clock. The front of the microphone points toward 12 o’clock. That’s normally where it is most sensitive. Move around toward 3 or 9 o’clock and the microphone becomes less sensitive.
Move toward 6 o’clock, directly behind it, and you reach the area of strongest rejection on an ideal cardioid pattern.
This doesn’t mean sounds behind the microphone become completely silent. That’s an important distinction.
A loud dog barking behind your microphone can still appear in the recording. A cardioid polar pattern reduces sensitivity from certain directions. It isn’t a magical noise-cancellation system.
Cardioid Doesn’t Mean Background Noise Disappears
This is one of the biggest misconceptions about directional microphones. Someone buys a cardioid microphone, starts recording, and then becomes disappointed when they can still hear their keyboard or air conditioner.
Cardioid means directional sensitivity. It doesn’t mean “background noise remover.”
If someone starts vacuuming directly beside you, changing your polar pattern isn’t going to make the vacuum disappear.
You still need a reasonably quiet recording environment.
Microphone Distance Is Important
Here’s one of the simplest ways to improve your podcast audio: Get closer to your microphone. Not ridiculously close.
But don’t put a cardioid microphone three feet away and expect it to isolate your voice perfectly. When your mouth is relatively close to the microphone, your voice reaches it strongly.
You can then set the recording level appropriately without needing to capture as much distant room sound. This can improve the balance between your voice and background noise.
The Proximity Effect
Many directional microphones exhibit something called the proximity effect. As you move very close to the microphone, lower frequencies can become more pronounced.
Your voice may sound deeper, warmer, or more bass-heavy. You’ve probably heard this sound on radio and podcasts.
Used carefully, it can create that close, intimate “broadcast” voice people often like. But too much isn’t always good.
Get extremely close and your voice might become muddy or overly boomy. you’re also more likely to create plosives. These are bursts of air from sounds such as P and B hitting the microphone.
A pop filter or windscreen can help, as can speaking slightly across the microphone instead of directly into it.
Cardioid vs. Omnidirectional
An omnidirectional microphone captures sound relatively evenly from all around it. That can be useful. Imagine several people sitting around one microphone. An omnidirectional pattern can capture voices arriving from multiple directions.
It can also be useful when you intentionally want to record the natural sound of a space. But that becomes a disadvantage when you’re trying to isolate one voice in a noisy room.
The microphone is designed to hear what’s happening around it. For a solo podcast recorded at a desk, I’d usually prefer cardioid.
For capturing a group or an environment with one microphone, omnidirectional may make more sense. It’s about the job.
Cardioid vs. Bidirectional
A bidirectional microphone, also called a figure-8 microphone, primarily captures sound from the front and rear while rejecting more sound from the sides.
Imagine two people sitting directly opposite each other with one microphone between them. One person talks into the front. The other talks into the back. A figure-8 pattern can work well for that arrangement. Cardioid works differently.It focuses mainly on one side.
For most solo podcasting situations, that’s exactly what you want.
Cardioid vs. Supercardioid
Supercardioid sounds like it should simply be “better cardioid.” That’s not really how it works.
A supercardioid microphone has a narrower front pickup area than a standard cardioid microphone. That can provide stronger rejection from certain side angles.
However, supercardioid patterns also have some sensitivity at the rear. That changes where you should place unwanted sound sources.
A narrower pattern can also be less forgiving if you move around while speaking. Move too far away from the microphone’s main pickup area and your voice level can change.
More directional doesn’t automatically mean better.
Cardioid vs. Hypercardioid
Hypercardioid goes even further toward a narrow front pickup area. It also has a more noticeable rear lobe than cardioid.
Hypercardioid can be useful when strong directionality is needed, but microphone placement becomes increasingly important.
For someone sitting at a desk recording a normal podcast, standard cardioid is often simpler.
You have enough directionality to help isolate your voice without needing to remain perfectly locked into a tiny pickup area.
Dynamic vs. Cardioid: What’s the Difference?
These terms are often confused. A dynamic microphone describes how the microphone converts sound into an electrical signal.
Cardioid describes the microphone’s directional pickup pattern. They’re not opposites.
A microphone can be both dynamic and cardioid. In fact, many popular podcast microphones are exactly that. You can also have a condenser microphone with a cardioid polar pattern.
When you’re shopping, think about these as separate characteristics. One tells you about the microphone technology. The other tells you where it listens.
Where Should You Put Background Noise?
If you’re using a cardioid microphone, take advantage of its rear rejection. Suppose your computer has a loud cooling fan. If possible, position the microphone so the noisy computer is toward the rear of the microphone rather than directly in front of it.
The same idea can apply to other predictable noise sources. Don’t just position the microphone based on what looks good on camera.
A few inches of movement or a different angle can sometimes improve a recording without costing anything.
Final Thoughts
A cardioid polar pattern means a microphone is most sensitive to sound coming from the front while becoming less sensitive toward the sides and reaching its strongest rejection toward the rear.
That simple characteristic makes cardioid microphones incredibly useful. They can help podcasters focus on their voices instead of capturing the entire room equally.
You don’t need to understand complicated audio engineering to use cardioid properly.
Put the sound you want in front of the microphone, keep the sounds you don’t want away from its most sensitive area, and you’re already using the polar pattern to your advantage.