What Is A Dynamic Microphone

by Matthew David | Updated: September 14, 2023

What Is A Dynamic Microphone

Have you ever wondered how singers belt out lyrics into those mesh balls on stage, or how podcasters get their voices recorded so clearly? Well, it all comes down to one little piece of technology: the microphone. Microphones might seem simple, but there’s actually a lot that goes on inside them to convert sound into an electrical signal. There are two main types of mics used in music and audio production: dynamic and condenser microphones. Both have their strengths and weaknesses that make them better suited for certain situations. In this guide, we’ll demystify exactly how both types of microphones work and when you should use one over the other. Let’s dive in!

How Microphones Work

Before we get into the differences between dynamic and condenser microphones, it helps to understand exactly what a microphone does. Inside every mic is a thin material called a diaphragm. When sound waves hit the diaphragm, it vibrates to match the frequency and volume of the sound. Attached to the diaphragm is a converter that transforms those physical vibrations into electrical signals. Those signals can then be amplified and recorded.

There are two main sizes of diaphragms used in mics. Small diaphragms are found in pencil mics and large diaphragms in studio condenser mics. The size affects the mic’s frequency response and polar pattern. Generally, small diaphragms capture more accurate high frequencies while large diaphragms provide a fuller, smoother sound.

Now let’s look at how dynamic and condenser mics differ in converting the motion of the diaphragm into electrical signals.

Dynamic Microphones

Dynamic microphones work using the principles of electromagnetism and induction. They’re actually quite similar to speakers, just in reverse! The diaphragm is connected to a coil of wire that sits inside a magnetic field. When the diaphragm vibrates from incoming sound waves, the coil moves back and forth inside the magnetic field. This induces an alternating electrical current that matches the motion of the coil. Pretty cool right?

In most dynamic mics, the coil is attached to a thin ribbon diaphragm to form a ribbon transducer. This allows the diaphragm to follow the nuances of the sound vibrations very accurately. However, the output signal is quite low. So the electrical signal gets boosted with a step-up transformer before being sent to the microphone output. Even with the transformer, dynamic mics tend to have lower output and sensitivity compared to condensers.

One unique property of ribbon dynamic mics is their bi-directional or figure-8 pickup pattern. This means they capture sound equally from the front and back of the mic, while rejecting sound from the sides. Ribbon mics are often used on guitar amps and drum overheads to take advantage of this pattern.

In general, dynamic mics are preferred for high volume and live sound settings. They can handle very loud signals without distorting and don’t require external power to operate. Typical dynamic mic uses include:

Condenser Microphones

Condenser microphones take a different approach to converting sound waves to electrical signals. Rather than electromagnetism, they use changes in capacitance between two plates to produce an audio signal.

Inside a condenser mic is a capacitor made of two plates, one is the diaphragm and the other is a fixed backplate. Incoming sound vibrations cause the diaphragm to move closer and further from the backplate, changing the capacitance between them. An electrical current is generated from this change in capacitance.

Here’s the catch: condenser mics require power to boost this signal to usable levels. This is why they need phantom power, typically 48V, from a mixer or audio interface. This allows condensers to capture sound with great detail and sensitivity. However, they can’t handle extremely loud signals without distorting.

Condenser microphones tend to be the choice for studio recording and acoustic instruments. Their nuanced sound reproduction results in crisp, clear vocals and accurate instrumental tones. Common condenser mic uses include:

To hear the difference between condenser and dynamic mics yourself, have a listen to these audio samples:

Direct Sound Samples

Dynamic Mic Audio Sample

Condenser Mic Audio Sample

Notice how the condenser mic sounds more open, airy and detailed, while the dynamic mic has a tighter, more focused tone. Neither one is necessarily better, they just excel at capturing sound in different scenarios.

Choosing the Right Microphone

So when should you use a trusty dynamic mic or a nuanced condenser? Here are some guidelines:

The key is choosing the right tool for the job based on your environment and sound source. While condensers tend to sound better for studio recording, a well-placed dynamic mic can still capture great vocal or guitar tones. Ribbon mics excel on guitar amps, even in the studio. So don’t be afraid to break conventions and experiment!

Microphone Specifications

To geek out on the tech specs, here are some key microphone characteristics to consider when choosing one:

While specs don’t tell the complete story, they can give you an idea of how a mic will perform. Just remember that sound quality matters more than numbers on paper!

In Conclusion

We’ve demystified the age-old question – what exactly is a dynamic microphone? In a nutshell:

Now that you understand the difference between these two main types of microphones, you can make informed choices for your next podcast, vocal booth, or drum recording session. Most importantly, don’t be afraid to go with your ears and find what works for the sound you want to achieve.