We call it by so many names—headphones, earphones, earbuds, headset, and so on. But these terms all refer to the same mini speakers that we stick into or, at least, place over our ears. We use this ear equipment for various auditory tasks—listen to music, do voice calls, watch movies, or play online games. They can also appear in different designs, colors, and shapes. Some are wireless, while others are wired. This article, then, aims to discuss a bit about the physics of headphones. Without being too technical, let us provide you with a brief discussion of these audio accessories that are hugely popular today.
While bigger speakers allow us louder audio levels, headphones offer added noise reduction and sound immersion. They allow you to isolate yourself from your surroundings as soon as you place that pair of headphones on your head and connect it to an audio source. You can use it on your smartphone, computer, or tablet. Most are compatible with any system, although some may have specified operating system compatibility. You can purchase them from just about any music store worldwide—from the cheapest make and model to the more expensive and advanced ones.
One superb feature of the headphones is the equipment’s plug-and-play function. Because they are meant to be portable, they are also designed to be user-friendly. Thus, you get to bring them along anywhere you go. You don’t have to install any software driver on your smartphone, for example, to make it work. But how do these headphones work, anyway?
Read on to find out how do headphones work, and let’s start identifying its different functions, brushing a bit through the physics of headphones.
How do headphones work?
As it happens, headphones work in the same way that speakers do. They convert electric energy into sound energy using designated magnets that allow air particles to vibrate, producing the audio that we hear. How do your headphones work? The digital audio is stored in a device such as your smartphone, computer, or tablet in the form of a data file that contains 1s and 0s. These 1s and 0s, audio sampling recorded using a mic, are sent to a digital-analog converter (DAC) when you push your audio device’s play button. The DAC turns these 1s and 0s into electronic audio signal that get to travel through the provided wires, entering your headphones.
The driver unit
Upon entry into your headphones, the electric audio signal arrives at the driver unit. The driver unit is of three types—dynamic, planar magnetic, and electrostatic.
Below is a brief description of each type:
Dynamic driver unit
The most common driver unit used by headphone manufacturers is composed of three components—a diaphragm, a permanent magnet, and electromagnetic coils. A dynamic driver primarily works due to its magnets. Each ear cup contains two magnets. One of these magnets is an electromagnet designed to move, while the other is a permanent magnet that does not move.
The electric current that arrives at your earcup goes straight to its electromagnet—the component that interchanges polarity based on the pattern or audio signal it receives. The rapid changing of the electromagnet’s polarity simultaneously gets attracted and repelled by your driver’s permanent magnet. This mechanism causes the electromagnet’s vibration. Because these electromagnets are connected to the diaphragm—a membrane that’s made out of thin material, the diaphragm vibrates as well. This process makes the air vibrate, producing sound.
Planar magnetic driver unit
The planar magnetic driver unit is similar to the dynamic driver unit. However, this one uses thin magnetic conductors that are distributed in the diaphragm. Several magnets are also behind the diaphragm that reacts to the electric current that passes through the incorporated conductors. The diaphragm and the permanent magnet then interact to produce sound. This type of driver is also referred to as the Orthodynamic driver.
Electrostatic driver unit
For this type, the diaphragm is the one that gets to move. This diaphragm sits in the middle of a couple of conductive plates—one plate is negatively charged while the other is positively charged. As soon as electric current travels through these plates, the thin diaphragm vibrates, making the air vibrate, which create sound waves and produces sound. Headphones integrated with this type of driver unit are expensive. However, many believe that these kinds of headphones sound far better than those incorporated with the other two types of drivers.
Types of headphones
There are several types of headphones. Here are several of them:
Open Back and Closed Back
Headphones, in general, are those that have a headband attached to them. They are either open back or closed back. Closed-back headphones are those with their ear cups fully sealed at the back. These headphones are designed in such a way that sound goes directly to your ears. They are also more capable of blocking or canceling out extraneous noise from your surroundings.
Open-back headphones are those with their earcups open at the back. They provide you with natural-sounding feedback, although they aren’t as effective in extraneous noise cancellation.
Earbuds
As we go further a bit into the physics of headphones, there is a need to touch upon the subject of earphones or earbuds. Earbuds follow the same process—they produce sounds that are directed at your ears. However, they do not have headbands and are typically made to stick into your ears, placed into your ear canal directly. This is why they can also be called in-ear headphones. They may not offer the same frequency response range as headphones do.
Noise-Canceling Headphones
However, some headphones—and earphones are more advanced because they have active noise-canceling functions. While a typical closed-back pair of headphones passively reduces extraneous noise due to their design, these noise-cancelling headphones can deftly reduce outside noise because they are incorporated with such a specific function. Hence, their audio quality is cleaner and clearer than most, making them perfect for listening to ambient noise.
Wireless Headphones or Bluetooth Headphones
Wireless headphones work exactly like their wired counterparts. When it comes to sound quality, the sound waves it produces depend on the components of the headphones you purchase. Since they don’t use any wires, these headphones work using Bluetooth connectivity. This is why most people refer to wireless headphones as bluetooth headphones.
Conclusion
It is necessary to understand the fundamental physics of headphones, especially if you plan to purchase one that efficiently provides you with superb audio quality. Drivers are essential as they allow your headphones to provide you with sound. You also must identify what type of headphones to purchase based on noise-canceling capacity. Now that you’ve understood how this device works, you don’t need to wonder how do headphones work anymore.