A headphone driver in the simplest form consists of a magnet, a voice coil, and a diaphragm. The magnet creates a magnetic field that interacts with the voice coil. The voice coil moves the diaphragm, which in turn reproduces sound. However, there are different types of headphone drivers that reproduce sound differently.
This post will cover the different types of headphone drivers, how they work, and how they affect your sound quality. Enjoy. You can also check out our informative headphones buying guide.
1. Dynamic Drivers
The most common headphone driver is the dynamic driver. A dynamic driver is a smaller version of the large drivers you see in the speakers in your home. Dynamic drivers are also known as moving coil drivers.
How a Dynamic Driver Works
Dynamic drivers work by converting electrical energy into mechanical energy. This mechanical energy is responsible for compressing air and converting motion into sound energy or sound pressure level (SPL). At its simplest, a dynamic driver consists of three components: a magnet, a voice coil, and a diaphragm attached to the voice coil.
Here are The Parts of a Dynamic Driver
In dynamic drivers, when a current is sent through, it travels to the voice coils and interacts with the magnet’s magnetic field attached to the driver. As audio signals travel through the voice coil, the musical waveform moves up and down, which causes the voice coil to be attracted or repelled by the magnet.
Dynamic Driver Diaphragm Moving Animation
As the voice coil moves, so does the diaphragm. The back-and-forth motion creates pressure waves in the air, reproducing sound. The larger the motion of the diaphragm, the higher the volume.
How Do Dynamic Drivers Affect My Music?
Regarding sound quality, dynamic drivers are good at reproducing the low notes or bass frequencies because of their ability to displace air.
However, at higher volumes, dynamic drivers are more susceptible to distortion due to a limited movement of the diaphragm. Smaller dynamic drivers like the ones in most headphones, on average, perform worse and are more likely to distort than larger dynamic drivers.
One of the ways to counter distortion is by using new innovative materials like Graphene. It is light and strong and can move quickly, reducing distortion and making it great for higher frequencies.
2. Balanced Armature Drivers
Balanced armature or BA drivers are the smallest of all headphone drivers, and because of their size, they are only available in earbuds, in-ear monitors (IEMs), and other in-ear headphones.
Balanced armature drivers were first developed for hearing aids and critical listening, but they have proved to offer improved fidelity and musical detail over traditional dynamic drivers.
The major advantage of balanced armature drivers is the small size. This leaves room for other components and allows multiple drivers to be combined for better performance. Balanced armature drivers are also combined with dynamic drivers in a configuration known as a hybrid driver.
How a Balanced Armature Driver Works
Unlike a dynamic driver, a balanced armature driver comes with more components that help it reproduce sound: the diaphragm, drive pin/rod, armature, conductive coils, and magnet.
These are The Parts of a Balanced Armature Driver Unit
First, an audio signal is passed through the conductive coil circuit. An armature is surrounded by the coils and suspended between two permanent magnets of different polarities. As the audio signal passes through the coil, it changes the magnetism of the armature and forces it to move in the direction of one magnet or the opposite.
The armature is linked to the diaphragm by the drive pin. As the armature vibrates by moving up and down, the drive pin transfers the motion to the diaphragm, which moves to reproduce sound waves.
How Do Balanced Armature Drivers Affect My Music?
Most single-balanced armature drivers perform poorly when reproducing the entire audible frequency range. They are, however, great for reproducing specific frequency ranges. Therefore, many in-ear headphones with balanced armature drivers will utilize multiple balanced armature drivers to reproduce a wide frequency response. Each driver is responsible for its own smaller range.
The splitting of the audio signal is made possible by a crossover that effectively sends the right signal to a driver that is best suited to reproduce them.
If you are a fan of bassy music, an only armature driver IEM might not be your best bet. Going for a hybrid type that features both a dynamic and balanced armature driver is better suited for producing low and high sound frequencies.
3. Electrostatic Drivers
Electrostatic headphone drivers use a different principle of generating sound than other headphone drivers. Electrostatic drivers employ the use of static electricity to reproduce sound. Because it is much harder to reproduce sound by static, electrostatic drivers require specialized amplifiers, usually called energizers, to boost the audio signal’s voltage while keeping the signal’s current to safe levels.
Electrostatic headphones come with hefty price tags, but that is the price you pay for their renowned extremely low distortion, impressive detail, and unmatched clarity.
How an Electrostatic Driver Works
An electrostatic driver consists of just two perforated metal plates, also called stators, and a very thin diaphragm. The diaphragm is coated with a conductive substance that allows charge to build up when a bias voltage is introduced. Electrostatic drivers use a very thin diaphragm, which, to put into perspective, is ten to twenty times thinner than a plastic bag.
Here’s The Working Principle of an Electrostatic Driver by Soundgearlab
The thin diaphragm is sandwiched between the stators. To move the diaphragm, electrostatic drivers use the principle of static electricity, where like electrical charges repel each other while opposite electrical charges attract each other.
The diaphragm is positively charged. When an audio voltage is introduced, the diaphragm is attracted to the negatively charged strator and, at the same time being simultaneously repelled by the positively charged strator. Alternating electric fields of the strator cause the diaphragm to move back and forth, reproducing sound.
How Do Electrostatic Drivers Affect My Music?
One of the advantages of electrostatic drivers is low distortion. The diaphragm is very thin, and it is the only thing moving, which avoids the distortions created by a mechanical performance like in a standard dynamic driver or balanced armature driver.
The accuracy and clarity of electrostatic technology to reproduce musical information without accentuating any frequency is very good. A great record will sound brilliant, but this will also unveil imperfections of poorly recorded tracks or poor audio sources.
4. Planar Magnetic Drivers
Planar magnetic drivers can be considered a crossbreed of dynamic and electrostatic drivers. Like dynamic drivers, they use a magnetic field around a conductor with an electrical current flowing through it to drive the diaphragm. Compared to an electrostatic, the diaphragm is a thin sheet of flexible transparent film, but unlike an electrostatic, the film has thin, flat electrical conductors inside.
In the world of headphones, planar magnetic drivers can be referred to as isodynamic, meaning equal force, or orthodynamic, A Yamaha marketing term.
Planar magnetic headphones have lower distortion, better bass reproduction, and tend to sound very coherent and spacious. However, most planar magnetic headphones are heavy, potentially making them uncomfortable. Notable manufacturers of planar magnetic headphones are Audeze and HiFiMAN.
How a Planar Magnetic Driver Works
The main components of a planar magnetic headphone are the diaphragm, which has very thin and flat electrical conducting wires, and an array of magnets placed in front of and behind the diaphragm, as shown below. The diaphragm is suspended.
Here is The Diaphragm of a Planar Magnetic Headphone
When an audio current is introduced, it passes through the conductors in the diaphragm. The current flow creates a magnetic field, which interacts with the isodynamic field created by the magnets surrounding the diaphragm and causes the conductors to move and, therefore, the diaphragm to move.
Both magnets have an equal force, which ensures that the relationship of the current flow to the force exerted by the diaphragm is always constant. This is regardless of the position of the conductors in their movement through the field.
How Do Planar Magnetic Drivers Affect My Music?
One of the notable effects of a planar magnetic driver is the bass response. The large surface area of the diaphragm coupled with a powerful drive of electromagnetic force helps move large amounts of air with authority. This gives off one of the best bass responses of any headphone driver.
Unlike dynamic drivers driven from the point the voice coil is attached to, planar magnetic drivers move freely over their entire surface. This greatly reduces distortion commonly associated with dynamic drivers when the cone starts wobbling in undesirable ways at higher frequencies.
5. Bone Conduction Drivers
Bone conduction headphones have drivers in them. However, bone conduction drivers work differently, unlike the previous drivers we’ve seen above. Bone conduction drivers are not concerned with creating sound waves that pass through the eardrum. Instead, they convert electrical audio signals into physical vibrations that travel through the cheekbones to our inner ears.
Though this is not a new technology, bone conduction headphones have improved and feature many consumer-level headphones. One notable manufacturer of bone conduction headphones is Aftershokz.
Bone conduction headphones are beneficial when the ears need to be left unobstructed, like jogging in high-traffic areas. People with hearing problems can also enjoy music using bone conduction headphones.
How a Bone Conduction Driver Works
To understand how bone conduction headphones work, first, we need to know how sound can be transmitted in the ear. There are two methods of how sound can be heard.
The first method is what most headphones use. It involves sound waves passing through the ear canal, the eardrum, the ossicles, and the cochlea that sends the sound information via the auditory nerve to the brain for deciphering.
How a Bone Conduction Headphone Works
The second method is how bone conduction headphones work. A bone conduction driver uses a piezoelectric crystal pressed against the cheekbone. When an audio signal flows through the driver, the piezoelectric crystal vibrates according to the direction and amplitude of the current.
As the driver vibrates, these vibrations are passed straight to the cochlea through the cheekbones. The cochlea picks up these vibrations and sends them to the brain to perceive as sound.
How Do Bone Conduction Drivers Affect My Music?
Though bone conduction technology is still evolving, the sound quality of bone conduction headphones is relatively poor. Suppose you seek headphones to listen to music at home or critically; these are not for you. No bone conduction headphones come close to sounding the same as other headphones.
Bone conduction headphones do not offer any active or passive noise cancellation. This is both a pro and a con. If you want situational awareness, then this is an advantage. However, the flip side of not covering our ears means that you will pick up any ambient noise with bone conduction headphones. This is a disadvantage, especially when looking for a more immersive listening experience.
