One of the most common accessories, if you are a music lover, should be the headphones.
In fact, they are one of the prominent items you would find on anyone’s head or ears. But, have you ever given a thought to how headphones work?
If we have initiated you into thinking over how the headphones are capable of bringing in the music to your ears, we will explain the concept in a finer detail.Click here to watch a simple 3-minute video on how do headphones work or continue with the guide…
How Do Headphones Work?
Well, you may have seen the huge loudspeakers emitting loud music through them at an event or concert. The headphones are equivalent to the stereo speakers and can rightly be considered to be miniature versions of the speakers.
The basic functionality of the headphones would be through the electromagnet and a cone – the cone is generally made of paper or any other suitable material. The combination of these components would be used to vibrate the air around and thus create sound waves.
What is the Underlying Principle?
The loudspeakers and headphones belong to the same family as long as their functionality is concerned. They work on the same principle. The basic principle of their working would be through converting the electrical signals into sound waves.
The source of the music sends the signal in the form of alternating electrical current. This current is fed through the cable to the miniature speakers within the headphone. These miniature speakers are referred to as drivers. The driver consists of a voice coil.
The alternating electrical current will then generates a magnetic field. The driver is connected to the cone that we mentioned above. This cone would move back and forth at a speed of around 20 and 20000 times a second. This affects the air around and creates the sound wave. This sound wave is fed into your ear.
That would be the explanation from a layman’s point of view. The major difference between a loudspeaker and headphone would be the size variation between them.
A loudspeaker would need to vibrate the air around the room to produce the sound waves akin to that form the source, while headphone would only need to vibrate air in your ear canal. That would explain the reason why they can be effective even with the smaller size.
What Are Headphones Made of?
Let us take the example of earbuds. They would essentially consist of six to seven components that make them up. All these components together would help you get an effective sound reproduction.
The insides of the earbud consist of a plastic disc. The disc has a slightly conical shape and has holes to let the sound waves reach your ear. It comes with a transparent metal coil attached to the centre. The magnet is the heaviest part of the speaker. The coil becomes an electromagnet when the electrical current flows through it.
The other end of the headphones is the connector that plugs into the source of the audio – in our case, the smartphone or any other portable media device. It fits into the audio output port on your device.
The connector takes in the sound waves in the form of electrical energy and feeds it to the headphones through the cable. The major areas of the connector are referred to as Tip, Ring and Sleeves. That should explain why the headphone connector is referred to as a TRS connector.
How do Noise Cancelling Headphones Work?
Have you heard of noise cancelling headphones? If you are an audiophile like we are, you should have, by all probability.
Noise Cancelling headphones are the best for listening to
In case of passive noise cancelling headphones, they come with sound absorbing materials and tend to be heavier than the regular headphones.
They block some of the ambient noise through their noise filtering functionality. These can be capable of filtering out the ambient noises at high frequencies. They are assumed to reduce the ambient noise levels up to around 15 to 20 decibels.
Active noise cancelling headphones go a step above the passive noise cancellation technology. They have a construction that can actively block the high-frequency sound waves effectively.
In addition, they also come with a functionality of handling the low frequency sounds as well. They have their own microphones. These microphones pick up the ambient noise and transmit it to the noise cancelling mechanism.
The mechanism creates an exact replica of the sound wave but creates in such a way that it is 180 degree out of phase with the original sound wave picked by the microphone. This will effectively erase the ambient noise. They are capable of doing away most of the ambient noise in the low-frequency range.
It should be noted that the noise cancelling headphones in the active category would need a battery for powering the system that involves the microphone and the noise cancelling circuitry within the earbud.
How do Headphones Work without Power?
While active noise cancelling headphones as explained above would need external power for their effective noise cancellation functionality, the normal headphones would not need any sort of power as such.
If you are using the normal wired headphones, you would have noticed that they do not come with any external power source. Does that mean they do not need any kind of power source for their operation?
Well, not exactly. They would need the power for the functionality that they are designed for. But, they would draw the power from the device that they are connected to.
Most headphones are connected to the source through an analogue cable. The cables transmit the sound waves in the form of electrical energy to the drivers inside the headphone assembly.
The audio sources (like your smartphone, MP3 player or for that matter any source that you have connected the headphone into) send in enough additional power to power the drivers. This energy requirement is generally quite low and ranges around 100 mW or much below and thus is not an issue to transmit through the analogue jack.
The Parting Thoughts
Well, that was how your headphones work – explained in the simplest possible language. We have focussed on making the concept understandable without relying on too much technical know-how.
The principle remain similar across all the manufacturers and headphone formats. The earbuds would come with the simpler design, while the larger headphones would offer you a slightly complex mechanism in tune with the principle we explained in the above paragraphs.
The basic technology used in the headphones would be called a Transducer technology. They would convert the electrical energy into the sound energy. The manufacturers have been adding a few extra technologies and features to their product line up.
In fact, the Shape, size, comfort and sound quality are a few basic features that you need to pay attention to when designing the headphones. Now that you are equipped with a good knowledge of what exactly makes a headphone and how do they work, it should be easier for you make a learned choice when opting for your next set of headphones.