How Does a Microphone Work?

“Is this thing on?”

We’ve heard it before. A gifted but eccentric investigator visits a small town to solve a mystery. While some cases are better left unsolved, the question of how a microphone works is pure electricity.

In this blog, we’ll examine the construction of dynamic and condenser microphones to learn what they do and how they do it, plus some everyday applications for these trustworthy tools of the studio and stage. 

WHAT DOES A MICROPHONE DO?

Microphones convert sound into electricity. This is true for live music, streaming, radio, phone calls, film, play-by-play sports—you name it.

Modern life wouldn’t be the same without microphones. Think about the number of broadcasts and recordings you hear every day—PA announcements at the grocery store, viral videos, video games, your favorite band’s livestreaming concert—they all use microphones to deliver the message. But how do microphones work? Are they all the same? Let’s find out.

HOW DO MICROPHONES WORK?

Microphones are transducers—devices that convert energy from one form to another—built with a small diaphragm attached to a wire coil (or membrane) that vibrates within a magnetic field.

A microphone’s job is to take the mechanical energy of a soundwave and turn it into an electrical signal. These signals can be amplified, broadcast, recorded, mixed, sampled, remixed, sent to effects processors, pressed to vinyl, uploaded to digital streaming platforms, or even minted on the blockchain and sold as NFTs.

When sound waves strike the diaphragm, the coil vibrates within the magnetic field, creating small fluctuations in electrical energy that travel through the microphone cable and out of a loudspeaker—which is just a big microphone wired in reverse.

WHY DO I NEED A MICROPHONE?

It’s easy to understand why a touring vocalist might want to bring their own microphone to a gig, but what about drummers? Gamers? What if you work from home? Maybe you’re an educator?

Here are some common microphone applications:

• Music recording
• Live music
• Video conferencing
• Content creation—Influencers, YouTubers, Twitch, etc.
• Livestreaming
• Journalism
• Public speaking
• Stand-up comedy
• Filmmaking
• Theater
• Remote learning

TYPES OF MICROPHONES

In modern applications, the most popular microphones are dynamic mics and condenser mics.

DYNAMIC MICROPHONES

Dynamic microphones, including the enCORE 100, pair their diaphragm and coil assembly with a permanently charged-up internal magnet. Sound waves hit the diaphragm, the diaphragm moves the coil of copper wire enclosed inside a magnetic field and bam! You’ve got signal.

With their robust bar-magnet construction, it’s no surprise that dynamic microphones are built tough to survive the rigors of live performance and extensive touring. Dynamic microphones have a powerful sound with strong midrange and a forgiving treble response, making them ideal for vocals and instruments on outdoor festival stages.

CONDENSER MICROPHONES

Condenser microphones, like the Blackout Spark SL, take a different approach. In a condenser microphone, the diaphragm is built of a delicate, negatively charged membrane suspended near a metal backplate. Soundwaves cause the membrane to move, changing the distance between the membrane and the backplate, which produces an electrical signal.

With their delicate capsules, condenser mics are the preferred choice for studio recording because they capture intimate details like the transient pick attack of an acoustic guitar, subtle ghost notes on a snare drum, or the faint breath between lyrics more accurately than dynamic mics.

Condensers typically have an extended frequency response up to 20kHz or higher, making them great for extra intelligibility while podcasting or enhanced realism while recording a band live in the studio. They excel as vocal mics, drum overheads, acoustic guitar microphones and even as a dedicated microphone for your next Twitch event.  

PHANTOM POWER

Condenser microphones need +48V phantom power to do their job. It’s complicated, but the short version is that phantom power helps condenser microphones produce enough electrical current to operate effectively. But don’t sweat it—that’s what the +48V button on your audio interface does. Just be sure to engage +48V before you unmute the channel to avoid sending a potentially speaker-shredding pop to your studio monitors or headphones.

Now that you know how a microphone works, it’s time to put microphones to work for you. Check out our Music blog for more microphone and recording techniques!