How Do Headphones Work?

How Do Headphones Work?
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    Headphones have weaved their way into our everyday life. Hardly anyone can claim to pass their day without their trusty headphones to keep unwanted noise and interactions at bay. Whether you’re training, commuting, studying, or even finishing your house-chores, headphones will always be your faithful companion, speeding away your boredom and making you hours bearable.

    General Mechanism of Sound Production

    In simple words, headphones convert the electrical energy from your device to sound energy that you can hear.

    The first step is converting a very long series of 1s and 0s into electrical energy that can actually pass through the wires of your headphones. In order for that to happen, those 1s and 0s have to go through a DAC (Digital Analogue Converter).

    After the electrical energy has passed through the wires, it’s now time for it to be translated into sound. That is achieved through a part common between both headphones and speakers; it’s called the driver/transducer. The driver consists of several smaller parts, which we will discuss later on in detail. However, all you need to know right now is that it has two magnets; one stable and another that moves.

    When the electrical impulses reach the electromagnet/the moving one, it changes polarity and rebels from the stationary magnet, then vice versa. This movement keeps on happening, causing vibration to other parts of the driver, like the diaphragm. This vibration leads to movement of the air, which eventually gives us sound energy.

    Parts of Ear/Headphones

    Jack

    It is divided into segments that house the wires coming from each mini speaker. Also, these segments allow for a better grip on the jack, making it easier to put it in or takeout it out. It might as well have a fourth segment for a microphone, which is the way with all the trendy headphones. 

    The jack is usually plated with gold or silver for both durability and aesthetic. You’ll find that the segments are mostly represented by black or white bands. Mostly headphones sport a 3.5mm jack, yet the less common 6.3mm jack has found its way into many headphones such as the Audez LCD-3 and the Beyerdynamic DT 1990.

    Wire

    Mostly, copper wires with plastic coverage are used. However, headphones have been a growing industry for so long and can offer luxurious options. Kevlar cables are manufactured from sturdy fabrics, the same fabrics that are used in bullet-proof jackets. This practically throws the possibility of your headphones tearing out of the window. Another option is tangle-free headphones. This is achieved through having flat wires rather than round ones.

    Earcup

    Although this might seem like the most basic of parts, the earcup/housing is what defines the headphones. It’s the first look that you take at a product, and that can determine a lot of things. It can be wooden or metal or plastic or any other material under the sun. There’s absolutely no limit, from your basic earphones to the most decorated headphones.

    Cover

    Mostly plastic, this is the part that has direct contact to your ear. It’s riddled with holes that allow the sound out but keep dust and earwax from getting in. Sometimes they’re lined with a layer of fabric for extra protection.

    Driver/Transducer

    Normally, we have three varieties of driver units; dynamic driver, the planar magnetic driver, and the electrostatic driver. However, they’re pretty similar, and the majority of headphones use the dynamic driver. This unit is composed of:

    • Copper Coil
    • Diaphragm
    • Electromagnet
    • Fixed Magnet

    Part and Function Relation

    Now, on to the physics of sound production. We will discuss how every part is crucial to the existence and quality of the sound that you hear.

    Jack

    As mentioned before, the jack is customarily divided into three, now four segments. The purpose of each segment is to house one wire coming from one headphone. Since each headphone gives out two wires, the secret here lies in sharing as there’s one segment that’s shared by both sides.

    Now when you insert the jack into your device, it connects on the levels of segments. The tapering end is called the Tip, the middle part is called the sleeve, and the uppermost part is known as the ring. Hence the conducting system is often called the TRS.

    Always keep in mind that each headphone is a closed circuit that requires two wires, as stated before. This leads us to the fact that every headphone must carry two ground-wires; these are the wires that entwine together and share a segment.

    Transducer

    The mechanism of the transducer has been alluded to in the beginning. The more detailed version is as follows. The electrical signal passing through the wires reaches the electromagnet, which allows it to keep switching back and forth from a polarized state to a non-polarized state.

    This change of state rebels and attracts the electromagnet to the fixed magnet. This movement travels on to the diaphragm, moving it as well. As the diaphragm vibrates, moving anywhere from 20 to 20,000 times, the air pressure around it changes as well, and that’s how sound is created.

    We’ll go through the different varieties of this unit, the first and most basic being the:

    • Dynamic Driver.

    This one is the most basic unit carrying the primary magnets and diaphragm.

    • Planar Magnetic Driver.

    These ones have one key difference from its predecessor; the shape/configuration of the magnets. Here, instead of two rather bulky magnets, we have tiny wire-like magnets that are spread across the diaphragm. The fixed magnet is replaced with the same magnetic wires as well; this allows for perfect coordination amongst the magnets.

    • Electrostatic Driver

    This is the new thing in the world of headphones. Why use the magnet when you can make the diaphragm itself move. How? Easy, the diaphragm here isn’t a piece of plastic; rather, it’s a skeletal film that’s electrically charged. 

    This film is placed between two conductive plates; as the signal hits the film, it starts moving between the two plates creating vibration, and, as a consequence, sound comes out. Some people say that this specific driver is the best in the market today as the electrically charged film usually is lighter than air, therefore, providing unprecedented clarity. 

    Noise Cancelling Headphones

    Have you joined the wagon of Noise-Cancelling Headphones yet? What if I tell you that every headphone you ever bought already had some measure of noise cancellation. This category of noise-cancellation is known as Passive Noise-Cancellation. 

    This is achieved through the material itself, the cover, the diaphragm, and the isolating seal all help in keeping the high frequency/shrill and loud sounds out of your ear.

    That’s not what we’re here to discuss, though. The new Apple AirPods retail for 250$, there must be a reason why people are prepared to pay that obscene amount of money for such a small device.

    The reason behind such a price tag is the technology of noise cancellation. In simple words, these headphones don’t just carry sound; they create it. When unwanted sound waves make their way into the headphones, they interpret them and create sound waves opposite to them (180 degrees flipped). Just like in an equation, opposites cross out each other. 

    This means that such devices will need a power source to provide energy for sound creation; these headphones always carry a battery that amounts to such prices. This is known as Active Noise-Cancellation.

    Final Thoughts

    The industry of headphones had started way back in 1910 when the first set was developed by Nathaniel Baldwin from the receiving end of a telephone piece. Ever since they have evolved non-stop to suit our needs and no doubt, they’ll keep growing. The market is exceptionally varied nowadays that you can buy a pair of headphones for five dollars or five thousand dollars. The choice is yours.

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    How Do Headphones Work?
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