Whether you’re amplifying noise at a concert of thousands or drowning out the sounds of home while on a work call, the basic technology of each speaker system is the same.
Headphones are the (at times lifesaving) miniature versions of traditional speakers. To understand how headphones work, therefore, we’ll take a deep dive into the mechanics of speakers in general.
But before we jump straight into the engineering-meets-physics deep end, let’s cover some of the science behind sound itself.
How Headphones Work
If you’ve ever seen speakers “bumping,” you may already know that though sound is unseen, it’s actually created by movement. Vibrations hit the surrounding air molecules and form a sound wave. This wave flows into your eardrum (which then also vibrates) and your brain translates the vibration into what we perceive as sound.
Of course, thousands of hours of reading are required to fully understand the nuances—like pitch and pressure—of sound and how they’re created. For our purposes, it’s mainly important to understand the basics: just as the strings of a guitar or your vocal cords vibrate to create sound, so do headphones. And the way in which this vibration is achieved is a fascinating feat of engineering.
The Parts of Headphones
Though different headphone models boast all sorts of bells and whistles, the universal components of headphones are pretty standard:
- Driver: the main part of the headphone that emits sound. It’s composed of:
- Voice coil: a threaded copper wire that becomes charged with current to create an electromagnetic field.
- Magnet: Magnets are fixed to the voice coil in order to move the driver.
- Diaphragm/Cone: a circular piece of etched plastic that vacillates to create the sound waves specific to the audio you’re listening to.
What happens when you play a song?
- The driver receives a signal (alternating electrical current) from the music player.
- The signal passes through the voice coil.
- The voice coil generates an electromagnetic field.
- A dynamic current runs through the electromagnetic field, which attracts and repels the fixed magnet.
- This moves the attached diaphragm, which disrupts the surrounding air pressure to create sound waves.
- Your brain translates the sound waves to what we perceive as music.
If you’re more of a visual learner, I highly recommend this video, which covers each part of the driver and how they work together to make sound.
How Do Different Types of Headphones Work?
As a newly minted headphone genius, you may be wondering what types of headphones use this technology to their best advantage. Various types of headphones offer different experiences and model their technology to best fit the experience they’re trying to achieve.
The type of headphones you’ll like best is less about the technology and more about personal preference and budget. If you’re looking for your perfect pair of headphones, we’ve reviewed some of our favorites here.
In the meantime, the technology behind the different types of headphones is super interesting, whether or not you’re on the market for a new pair.
Over-the-Ear Headphones: Open Back vs. Closed Back
Headphone that fully cover your ears are designed in two different ways:
- Open Back: drivers are exposed in the back
- Closed Back: drivers are covered in the back
Open-back headphones let more air into the diaphragm. This creates what’s described as a softer, more natural sound. If you prefer the sound of speakers, you would likely also enjoy an open-back headphone. The downside to this design is that you can more easily hear the sound of your surrounding environment, and those around you can hear what you’re listening to.
Closed-back headphones prevent ambient noise and give you more privacy, but the closed-off design sacrifices some quality of amplification and overall sound. They’re what’s recommended for the guy on the train listening to heavy metal, by all of his fellow passengers. In other words, the added privacy and noise-canceling features are often well-worth the sacrifice for the average user.
If loudspeakers are the Great Dane of the speaker world, earbuds are the teacup poodle. Still a dog, just smaller—and a less impressive bark, generally speaking. But what earbuds lack in sound quality they make up for in convenience. Most earbuds offer a closed-back design, but if you’re looking for an open-back feel with the earbud’s low-profile, keep an eye out for small vent holes in the back.
Noise cancelling headphones have the added feature of limiting the amount of outside noise you experience while wearing headphones.
There are two types of noise-cancelling headphones:
Passive noise-cancelling headphones use a closed-back driver and seal around your ears to block outside sounds.
Active noise-cancelling headphones are potentially the coolest bit of technology information we hope you take away from this article. They deploy a tiny microphone to take in surrounding noise and output a sound wave that’s the exact opposite—tricking your brain into ignoring ambient sounds.
In the end, whether you’re using earbuds or a loudspeaker, the technology is the same at its bare bones. Understanding this technology can help us understand the basic concepts of engineering and how our brains perceive the outside world. Or, it can just help you pick out a nice new pair of headphones.