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What Is a Microphone? How Do They Work? (Answered)

I often get asked what a microphone is. In this post, I will answer this question and explain more about microphones and how they work.

If this post helps you, share it with a friend!

What is a microphone? How do they work? (answered) - audio apartment

Microphones are arguably the most important part of a home studio. After all, you need something to record sound, don’t you?

This post will cover everything you need to know about microphones. We’ll discuss how microphones work and provide tips on choosing the right one for your needs. So, whether you’re a beginner or an experienced audio professional, this post is for you!

Image of a dynamic microphone in a microphone stand. Source: pixabay
Image of a dynamic microphone in a microphone stand. Source: Pixabay

What is a microphone? Microphones are transducers that convert sound pressure into an electrical signal. Microphones are used in the music industry for recording audio.

What is a microphone?

A microphone is a device that picks up sound. It does this by turning the vibrations in the air into electronic signals. They are used in the music industry to record audio.

How do microphones work?

A microphone is a device that transforms sound waves into an electrical signal. A microphone’s capsule has a little diaphragm on a moving coil within. Sound waves cause the diaphragm to vibrate. This results in the coil oscillating in the magnet’s field, creating an electric current.

But it’s not quite that simple. There’s much more to microphones, including diaphragm size, condenser vs. dynamic mics, and polarity.

What is a diaphragm?

To fully understand microphones, it is necessary first to understand the diaphragm, which is a crucial component of any microphone. Diaphragms function like miniature speakers and are made of a thin sheet (often plastic), a magnet, and a coil (the electrical conductor). The diaphragm vibrates in response to acoustic energy, producing a voltage.

Small diaphragm

Due to their compact size and lightweight, small diaphragm microphones (also called “pencil” microphones) are excellent at capturing high frequencies and maintaining a stable polar pattern. Because of this, you’ll often find them on acoustic instruments like pianos, snare drums, and acoustic guitars.

Large-diaphragm

Microphones with a broad diaphragm offer better sensitivity and a wider frequency response, resulting in a fuller sound. These mics are often used for recording voices, bass drums, and occasionally, a live room for a warmer sound.

Condenser microphones vs. dynamic microphones

Not all microphones are the same. Let’s take a look at the difference between condenser and dynamic microphones.

Condenser microphones

Condenser microphones are best for capturing vocals and high frequencies. Condenser mics often referred to as “capacitor mics,” are typically used in recording studios because of their high fidelity and precision.

A condenser microphone is like a capacitor with some extra features. A capacitor is a passive electrical part that stores energy in an electric field for a short amount of time. Two parallel plates are used to create a capacitance in a capacitor. As the distance between the two objects gets smaller, the capacity to hold an electric charge, or capacitance, increases.

A condenser microphone’s diaphragm is hung on a solid plate and weighs very little. The diaphragm shifts in response to the pressure of sound waves. When sound waves hit the diaphragm, they vibrate, and the distance between the plates changes. The resultant change in capacitance represents the acoustic energy from the input source in electrical form.

If you are looking for one of the best condenser mics in the market, look no further than the Audio Technica AT2035. This is a well-reviewed mic that won’t break the bank. And this unit below comes with a ton of extras. Check it out!

  • KIT INCLUDES: Audio-Technica AT2035 Cardioid Condenser Side-Address Microphone | AT8458 Shockmount | 5/8"-27 to 3/8"-16 Threaded Adapter | Protective Pouch | Audio-Technica 2 Years Limited Warranty | H&A Reflection Filter (Silver) | Reflection Filter Tripod Mic Stand | Pop Filter with Gooseneck and Adjustable Knob | H&A Elite Pro 10' XLR M to XLR F Microphone Cable with Rean Connectors | Closed-Back Studio Monitor Headphones
  • STUDIO AND LIVE: Exceptional Detail and Low Noise, The performance of this side-address mic makes it an excellent choice for both studio and live applications.
  • HOME STUDIO: With its smooth, natural sound, the AT2035 is ideal for musicians, streamers, podcasters, and other content creators.
  • PROFESSIONAL PERFORMANCE: Professional Extras, The AT2035 is equipped with a switchable 80 Hz high-pass filter and 10 dB pad, and comes with a custom shock mount.
  • The Audio-Technica AT2035 Cardioid Condenser Microphone is a well suited solution for home studios, project recording and live sound reinforcement alike. The side-address condenser microphone features a cardioid polar pattern for minimal feedback and off-axis noise. The element and output stage combine to produce a smooth yet natural audio quality with low noise.

Dynamic microphones

The dynamic microphone is the industry standard. They’re low-priced, long-lasting, and sound great. Dynamic microphones make a sound in the opposite direction of a normal speaker by suspending a moving induction coil in the field of a magnet.

Professional recording studios often use dynamic microphones because they are sensitive to sudden changes in sound and can handle loud volumes. This makes them an excellent option for close-miking very loud sources like a drum set or bass guitars.

Studio engineers often put an in-line preamp between a dynamic microphone and the console or microphone preamplifier. With the help of an in-line preamp, you can boost the signal and get the most out of a dynamic microphone, which is often a low-output instrument. Using an in-line preamp may drastically change even the most basic dynamic microphone, resulting in more professional-sounding recordings.

If you’re looking for the best dynamic mic on the market, look no further than the Sure SM7B. This mic is the primary choice for podcasters and vocalists.

  • ONE MICROPHONE FOR EVERYTHING - Studio Recording, Home Recording, Podcasting and Streaming. The SM7B Is Trusted By The Worlds Leading Vocalists, Podcasters and Streamers.
  • STUDIO VOCAL RECORDING - The SM7B’s Dynamic Cartridge With Smooth, Flat, Wide-range Frequency Response Produces Exceptionally Clean and Natural Reproduction Of Both Music and Speech.
  • PODCAST and BROADCAST - Found In The Top Podcasting Studios Around The World, The SM7B Air Suspension Shock Isolation and Pop Filter Eliminate Both Mechanical Noise And Breathiness. So Words Get Through And The Rest Stays Out Of The Mix.
  • STREAMING CONTENT - Professional Live Streaming Starts With A Microphone Capable Of Capturing Exceptionally Clean And Natural Reproduction Of Both Music And Speech. The SM7B Has Been A Pioneer In Such Abilities For Decades.
  • PROFESSIONAL XLR CONNECTION - The XLR Connection Along With An Audio Interface Allows You More Control Over The Sound — Thus A Better Overall Sound Quality. At least 60dB of gain is recommended to get that iconic warm and balanced tone most commonly associated with the SM7B.
  • CLASSIC CARDIOID PATTERN WITH UNIFORM CAPTURE - The SM7B Cardioid Pattern Is Designed To Reject Off-axis Audio, So You Can Sing Or Speak At A Comfortable Angle And It Captures The Sound, Just As You Want It, With Minimum Coloration.
  • SHIELD YOUR SOUND - We Added Advanced Electromagnetic Shielding To Defeat Hum From Computer Monitors And Other Studio Equipment.
  • CLOSE-MIKING STUDIO APPLICATIONS - The SM7B Shines When Used For Close-miking Instruments and ASMR Audio Where Warm And Smooth Full-frequencies Are A Must.
  • QUALITY IN THE DETAILS - Rugged Construction For Securing The Microphone Cartridge. Detachable Close-talk Windscreen And Switch Cover Plate Included. Bass Rolloff And Mid-range Emphasis (Presence Boost) Control With Graphic Display Of Response Setting.
  • WHAT’S IN THE BOX - Shure SM7B Vocal Dynamic Microphone With One A7WS Detachable Windscreen And One RPM602 Switch Cover Plate. Free 2-year Warranty Included.

What are microphone polar patterns?

The polar pattern of a microphone shows where it picks up sound best and where it doesn’t pick up sound as well. There are generally six different types of microphone polar patterns:

  • Directional
  • Bidirectional
  • Omnidirectional
  • Cardioid
  • Supercardioid
  • Hyper-cardioid

Directional microphones

Mics that are directional, or unidirectional, are adept at picking up sounds coming from a certain direction, making them a good choice for recording in noisy environments.

Bidirectional microphones

Bidirectional microphones, sometimes called “Figure 8 microphones,” capture sound from the east and west while rejecting noise from the north and south. They are especially good for recording phone conversations because they can pick up sound from more than one direction.

Omnidirectional microphones

Sound from any direction may be picked up using an omnidirectional microphone. Omnidirectional microphones can pick up all the sounds in a given area, but they don’t do a good job focusing on a single subject when there is a lot of background noise.

Cardioid

The cardioid pattern is about the shape of a heart, which is how it got its name. It is most sensitive to sounds coming from straight ahead and to the sides, while it ignores sounds coming from 180 degrees in the opposite direction. Mics with a cardioid, super cardioid, or hyper-cardioid pattern filter out everything but the singer’s voice, keeping the signal clear and stopping feedback.

Super-cardioid

The super-cardioid mic has a wider acceptance angle, taking in sound from about 180 degrees, but it also rejects more sound from the sides.

Hyper-cardioid

At 180 degrees, the hyper-cardioid can pick up an even wider range of frequencies. However, it can’t pick up frequencies at 90 and 270 degrees. For example, if you’re making music in a loud room or studio, you’ll want to pay attention to polar patterns.

What are the different types of microphones?

Let’s take a look at some different types of microphones.

Lavalier

A lavalier microphone also called a “lavalier,” is a small headset microphone that actors and public speakers wear to freely use their hands while using the microphone. They are typically small and unassuming. Small clips are typically included to facilitate attachment to collars, ties, and other clothing.

Shotgun Microphones

Shotgun microphones are long mics and are often used in film and TV production to pick up sounds from a distance.

Laser microphones

Laser microphones use the vibration of surfaces affected by sound waves to pick up sound. This is because vibrations cause the angular speed of the reflected lasers to change, which is then taken as sound. Laser microphones are useful when capturing audio from a great distance.

Ribbon microphones

Ribbon microphones consist of a magnetic field and a narrow strip of conductive metal. Typically, the ribbon is fabricated from a material like aluminum, duralumin, or nanofilm. When sound waves hit a microphone, they cause the ribbon to move, turning it into an electrical signal. Ribbon microphones are often utilized in recording studios because of their natural sound.

Image of a condenser microphone in a stand with a headphone beside it. Source: john wolf, pexels
Image of a condenser microphone in a stand with a headphone beside it. Source: John Wolf, Pexels

What is the frequency response?

The frequency response of a microphone describes the range of frequencies (low to high) that it can pick up. This range’s lowest and highest hertz values are used to identify it. A good vocal mic would have a frequency response of around 80 Hz to 15 kHz. A bass drum mic should start at 30 Hz or lower, whereas a snare and tom mic should start at 50 Hz or lower.

What are response curves?

The response curve of a microphone is the profile of its frequency sensitivity. It has the shape of a curve on a graph because its minimum value is zero, and its maximum value is also zero. Local peaks and valleys within this general curve will make one microphone different from another and better for use in some situations. If you want your voice to come across clearly, you may want to invest in a microphone that boosts the high midrange.

The microphone’s sensitivity is the lowest audible sound level the device can pick up. If nothing else, remember that the lower the number, the more sensitive the microphone should be.

What is SLP?

Sound pressure level (SPL) is measured in decibels (dB). It’s the opposite of sensitivity, specifying the loudest sound a microphone can pick up. This is crucial if the microphone handles very loud instruments, like drums. An SPL of 100 dB is considered normal, while an SPL of 130 dB is very loud.

What is the proximity effect

The proximity effect is an important part of a microphone. As the sound source gets closer to the microphone, the low-frequency sounds get louder because of the proximity effect. A recording engineer could put the mic close to a low-frequency instrument and use the proximity effect to make the low-frequency instrument stand out. The proximity effect is more prominent with condenser microphones than with dynamic ones.

If you want even more tips and insights, watch this video called “A Quick Guide to Microphones” from the Soundfly YouTube channel.

A video called “A Quick Guide to Microphones” from the Soundfly YouTube channel.
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Frequently asked questions (FAQ)

Do you still have questions? Below are some of the most commonly asked questions about microphones.

Do microphones need a power source?

No battery or other power source is needed for a passive microphone. They are not equipped with any internal amplification (though passive step-up output transformers can boost the output voltage of a passive microphone).

Which mic is best for vocals?

Many artists and sound engineers like to use a cardioid condenser microphone with a big diaphragm when recording vocals in a studio. This mic calls for a flat polar pattern, a boost in the presence range, and a natural frequency response.

What is the best type of microphone?

It depends. However, condenser microphones are the most popular option when picking up subtleties in a speaker’s speech since they reproduce high frequencies the best. Transients, or the highest points in a sound wave, are reproduced more accurately due to their high-end responsiveness.

Conclusion

There is more to a microphone than what may be found in its technical specs. Structure, metal type, and manufacturing accuracy may significantly impact a product’s effectiveness. For this reason, it’s reasonable to call pricing a key criterion. It’s important to remember that the only way to discern the differences between an excellent microphone and a poor one is to listen.

We hope you now know everything you need about microphones so that you can confidently choose your new microphone.

This article covered what a microphone is, the different types of microphones, and how the microphone works. Here are some key takeaways:

Key takeaways

  • A microphone is a device that records and plays back sound.
  • A microphone is a device that transforms sound waves into an electrical signal.
  • Diaphragms function like miniature speakers and are made of thin sheets.
  • Condenser microphones are best for capturing vocals and high frequencies
  • Dynamic microphones are one type of microphone that consists of a diaphragm, a coil, and a magnet.
  • In a dynamic microphone, the audio signal is generated by the motion of a conductor within a magnetic field.
  • The polar pattern of a microphone shows where it picks up sound best and where it doesn’t pick up sound as well.
  • Extra tips
    • The loudspeaker, located at the other end of the audio system, is also a transducer, converting electrical energy back into audible sound.
    • Power is important for establishing the capacitor plate voltage, which is also needed to power the microphone electronics.
    • Crystal microphones, like carbon microphones, were employed in early telephones in the 1930s.
    • You will achieve a much more consistent and coherent sound when recording in stereo if both microphones respond the same.
    • Due to their enhanced sound quality and long lifespan, digital microphones have also seen a surge in popularity in recent years.

So, what microphone do you prefer to use? And did I cover everything you wanted to know? Let me know in the comments section below (I read and reply to every comment). If you found this article helpful, share it with a friend and check out my full blog for more tips and tricks on music production. Thanks for reading, and never stop making music.

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Audio Apartment Author
Written By Andrew Ash
Hey there! My name is Andrew, and I've been making music since I was a kid. I now run this blog all about home studios and music production. If you want to improve your home studio setup, this is the place for you!

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