How Do Headphones Work? [The Definitive Guide Of Different Headphones]
- 28 Jan, 2019
Have you ever asked yourself, “How do headphones work?” It is important to know because this helps you to appreciate how important and interesting they are.
You may argue that they are just a simple pair of small speakers that are either placed in or on your ears for listening to music, and they are portable compared to normal speakers.
However, knowing the answer to the question, “How do headphones work?” makes you more capable of narrowing down your search for the perfect pair of headphones in 2019.
If you have a good idea of how speakers work, then this shouldn’t be hard for you. Headphones work nearly identical to speakers.
How Does Sound Reproduction Work for Headphones?
Basically, headphones may be regarded as small-scale loudspeakers. Like speakers, their purpose is to transform electrical signals into equivalent sound waves.
There is a considerable scaling down of the required acoustic level because of the close proximity of the driver unit to the ear, requiring input levels in milliwatt instead of watts.
Usually, an electrical signal is sent to the drivers in the headset from a music source. The signal goes through the voice coil located in the driver, generating a magnetic field.
The voice coil is attached to a lightweight diaphragm, often made of paper-like material. The changing electrical signal in the coil causes it to move back and forth in the magnetic field.
This also makes the diaphragm move back and forth. The motion causes the air to move, generating sound waves, which can be heard by your ears.
How In-Ear Headphones (Earbuds) Work?
Earbuds (in-ear headphones) are miniaturized headphones. They take music as close to your eardrums as possible.
The result is twofold: audio quality that is clear, and because the earbuds go right in your ear, they block out any incidental environmental noise.
Most in-ear headsets feature a sealed plastic (closed back earphones) and some are equipped with vent holes (earbuds that allow ambient noise).
How Do Earbuds Work?
Earbuds work in a similar way as loudspeakers and regular headphones, but they have a conical structure that fits into the ear.
The cable to each earbud carries an electrical signal from the sound source to the speaker. The coil that is attached to the magnet is transformed into an electromagnet when an electric signal goes through it.
The coil is attached to a transparent plastic cone. The electromagnet causes the cone to move, producing sound waves.
How Bigger Headphones (Over Ear and On Ear) Work?
If you have an idea of how loudspeakers work, then you can easily understand how headphones, either over-ear or on-ear, work.
How Do Headphones Work?
If you crack open the enclosure of just any headset, you will find similarly engineered components across the board.
Inside the headphone (both over and on ear) enclosure, you will find the driver unit assembly in which all the magic happens.
As I have earlier mentioned, the part that generates sound is known as the diaphragm, which is most commonly referred to as a cone when dealing with loudspeakers.
The diaphragm is vibrated or pulled back and forth at rapid succession, pushing the air surrounding the headphones, thus producing sound waves.
If you remove the diaphragm from the driver unit assembly, you will find two important parts: the magnet (type and strength vary depending on the model) and the voice coil.
When you play music through your headphones, you are outputting a certain amount of current through the cable.
The current goes directly into the concentrated voice coil, creating an electromagnetic field. The field move the coil up and down, and since it is attached to the diaphragm, it pulls the diaphragm, generating sound.
Headphones Drivers Explained
You now have the answer to the question, “How do earphone work?” However, you can choose the best model if you know the parts and function of earphone. The most important part to consider is the driver unit.
- Planar Magnetic Driver Unit
In principle, the traditional driver unit (dynamic driver) is very simple, and in practice not so much. The driver design gets more complex when talking about the planar magnetic driver unit.
A planar magnetic driver is actually rectangular in shape. Within the rectangle, there are little vertical lines and metal bars that run horizontally.
The horizontal metal bars are referred to as the diffusers and the vertical lines are made of a sheet membrane that features electrically conductive wires that run up and down between two different magnets.
When current goes through the conductive wires, a magnetic field is generated, which work together with the isodynamic field generated by the magnets.
The two fields cause the conductors to move, which in turn causes the diaphragm to move, thus producing sound.
- Electrostatic Driver Unit
Electric headphones are a unique design in the market. They minimize the problems experienced when using headphones with dynamic or planar magnetic drivers.
Headsets that use electrostatic driver units have an extremely light diaphragm that has little inertial potential.
The diaphragm is sandwiched between two thin, perforated metal plates and a charge of static electricity is placed on it.
When an audio signal, boosted in amplitude by your headphone adapter, is fed to the plates, the diaphragm is uniformly attracted to the plates, producing smooth, low-distortion sound.
Open Back vs Closed Back Headphones Work
Headphones are available in two major designs: open and closed back.
This design focuses more on comfort and audio quality, making it most convenient for critical as well as extended listening periods.
The back of the headsets is open, preventing comb filtering, allowing sound to travel both ways easily and normally with little isolation.
For superior comfort and coziness, most reference open-back headphones are equipped with bigger cushions than the outer ear, and the headband exerts little pressure on your head.
Open-back headphones tend to be lighter and more comfortable, but the design has a couple of potential faults.
First, external noise can come through the open back; so, they are not ideal for noisy surroundings. Second, the headsets may bleed into the mic if the volume is too loud.
This design focuses on maximum isolation between external noise and sound generated by the headsets. This makes them highly resourceful in recording music compared to the open back design.
The earpiece of these headsets has a sealed back that entirely closes the backside of each speaker. This generates little to no leakage, even at high volume levels.
The design of closed-back headphones offer superior sound quality, but it has a number of demerits that you may be concerned about.
The sealed cups means some sound reflects back to cause comb filtering. This style is also not suitable for extended listening as the pressure applied to your head can cause discomfort.
How Do Noise Cancelling Headphones Work?
There are two types of noise-cancelling headphones: passive and active. Passive noise cancelling earphones work like earmuffs, which prevent sound from reaching your eardrums.
Active noise-cancelling headsets go a step further than the passive ones. Active headsets provide a physical barrier that blocks high-pitched sounds. At the same time, they actively erase lower frequency sound waves.
Here’s How Active Noise Cancelling Works
A tiny microphone captures surrounding noise. An electronic system in the headsets analyses the noise waves, creating peak and trough patterns.
Therefore, whenever the noise wave peaks, the electronic wave troughs, cancelling out the peak. Your headphone speakers play the anti-sound waves, neutralizing the ambient noise.
Noise-cancelling headsets can block approximately 70% of outside noise. They work well in areas with low-frequency waves, such as open offices, trains, and planes.
How Do Wireless Headphones Work?
Wireless headphones send the audio signal through a wireless technology, such as radio frequency (RF) or infrared (IR).
- RF Headphones
These are the best wireless headphones for TV. They come with an RF transmitter that connects to your TV via a 3.5 mm jack or RCA cable. Have a coverage of up to 300 feet.
Connect the transmitter to the power supply using the AC adapter and then switch it on. The headphones and the transmitter pair automatically.
Usually, the pairing indicator lights constantly blue when an active link is established between the two devices.
- IR Headphones
Like the RF headsets, IR headphones do normally come with an IR transmitter that connects to an audio source. They have a restricted coverage.
The headphones connect to the transmitter in the same way as the RF headphones, but they use infrared instead of radio waves and they require a direct line of sight to pair successfully.
How Do Bluetooth Headphones Work?
Bluetooth headphones connect through radio waves to a Bluetooth-enabled audio source, such as a smartphone or dongle that is connected to a TV. They have a coverage of up to 50 meters.
As soon as you turn Bluetooth on, the audio source will begin to search for the Bluetooth headphones. The headsets need to be in discoverable mode for you to be able to pair them with the Bluetooth-enabled device.
In some cases, you may need a passcode to pair the devices successfully. The Bluetooth devices do usually connect over a 2.4 GHz radio band, which is license-free.
How Do Bone Conduction Headphones Work?
Bone conduction headphones do not use actual sound to communicate, but uses the vibrations generated by the sound.
This technology bypasses your eardrums. In bone conduction, your headphones convert sound waves into vibrations that are directly conveyed to the cochlea.
Bone conduction headphones have a number of benefits over traditional models. They less likely contribute to hearing loss because they bypass the eardrum.
When I tested a pair of bone conduction headsets, I found that the sensation isn’t off-putting at all. The audio quality; however, is not so great.
How Do Headphone Jacks Work?
A headphone jack is an electrical connector normally used for audio signals. It usually has two, three or four contacts.
The two-contact is called TS connector, three-contact is called TRS connector, and four-contact is called TRRS connector.
The T refers to tip (left channel), the R refers to ring (right channel), and the S refers to sleeve (ground). A TS connector carries a mono signal, a TRS connector carries two signals, and a TRRS connector carries three signals.
The headphone jack is available in three sizes: 6.35 mm, 3.5 mm, and 2.5 mm. The most commonly used size is the 3.5 mm jack.
The TRS headphone jack on stereo headphones carries the left and right channel signals when connected to an audio source.
The TRRS headphone jack on stereo headphones carries the left, right, and microphone signals when connected to an audio source. TRRS is the most popular headphone jack on the market.
How Do Headphone Wires Work?
All types of headphones with their cables can plug into the headphone jack, if the jack and cable are engineered to fit together properly.
A headphone cable that connects to a TRRS jack reveals six wires when cut:
- Right audio (red)
- Right audio ground (green)
- Left audio (blue)
- Left audio ground (green)
- Microphone (yellow)
- Microphone ground (green)
There is also a synthetic core included for additional strength.
Nowadays, most headphone cables are sophisticated. They are integrated with a control panel for play, pause, change tracks, and control volume.
There are different headphone cable styles on the market, including:
- Optical cables: Designed from fiber tube and glass. They are suitable for fast transmission.
- Regular cables: Designed from ordinary copper material with plastic protection. They come with most in-ear headphones.
- Flat tangle-free cables: They are also designed from ordinary copper materials with plastic protection, but they are flattened to prevent tangling.
- Coaxial cables: They are made of copper core, insulation, and additional fabric. They are very durable as well as high performing.
- Fabric braided cables: They are normally referred to as hybrid cables because they are made of different materials for conduction and insulation.
We use headphones every day when listening to music, responding to a call, and recording music. They are popularly used across the globe.
They are the most preferred devices for private listening, whether to avoid disturbing others or to block the noisy world around you.
But, how do headphones work? I have provided you with detailed explanations that should help you understand what is going on inside your headphones.
Understanding the simple mechanisms helps you appreciate this unique masterwork. You will also be able to choose headsets that work best for your application.