This is part 4 in a series on Headphones and Their Drivers!
- What is Headphone Impedance?
- What is Sensitivity in Headphones?
- What is Output Impedance?
- What is a Headphone Driver? (You are here)
- What is a Planar Magnetic Driver?
Greetings mate and Welcome aboard!
Stuart Charles here, HomeStudioBasics.com helping YOU make sound decisions, so…
Embark on a captivating journey into the realm of audio technology, where a diverse array of driver types awaits exploration.
From the robust bass of dynamic drivers to the precision of balanced armature, each type offers a unique sonic experience.
Discover the nuanced clarity of planar magnetic drivers and the pinnacle of fidelity with electrostatic technology.
Whether you’re a seasoned audiophile or a curious newcomer, delve into the fascinating world of driver design and uncover the secrets behind your favorite sound experiences.
Introduction
When I was first introduced to headphones, it was in the lonely corners of my local drug store back in the mid-’90s. In other words, they were an afterthought.
Important?
Sure.
If you had a Discman (or Walkman if you’re older than me), headphones were required. But I never thought much about the quality of them. I had no clue there was such a thing as “high-end.”
That may sound completely ridiculous now, but back then there was no internet.
I didn’t have the luxury of typing a phrase into a box and instantly seeing a result.
Therefore, I considered those trashy drug store headphones “top of the line.” OK, I’m exaggerating a little, but nobody I knew was in any way shape or form aware of anything better.
Most people, including my dad, listened to high-end speakers, so I was simply never brought up prioritizing headphones.
That said, I’ve always had a passion for sound, but my obsession with headphones didn’t materialize until much later on – and way before I started this blog in 2014.
It’s important to understand that anything producing sound waves has a driver, and some of the high-end model headphones have what are called angled drivers.
But What Is A headphone Driver?
The drivers inside of your headphones are responsible for converting the electrical signal into the sound that you hear, by creating a current with a conductor, through a magnetic field that moves a diaphragm, in effect creating sound.
- Check out How Headphone Dynamic Drivers Work!
Think of them like tiny loudspeakers inside of the earcups. A driver unit is comprised of:
- A permanent magnet that creates a magnetic field. The magnets are made from rare-earth ceramic materials—most commonly samarium-cobalt and neodymium-iron-boron.
- Voice coils. Responsible for moving the diaphragm that creates the sound you hear, by providing a linear motion back and forth when driven by an electrical audio signal. Since they are made of copper, they cannot create a charge by themselves. This is where the current comes in.
- A diaphragm. Moves back and forth, creating sound waves.
In a nutshell:
The magnetic field created by the permanent magnet interacts with the magnetic field created by the voice coil.
This creates the movement of the voice coil up and down, which in turn moves the diaphragm linearly, creating sound waves.
It’s worth noting that small vents with foam are integrated into the driver area to mitigate the acoustic impact of sound trapped behind the diaphragm. This subtle design element distinguishes between a smooth, even frequency response and a more erratic one.
Additionally, the motor structure of the driver can potentially compromise the overall sound quality if not properly optimized. The diameter of the diaphragm, typically listed in the headphone specifications, plays a crucial role in determining sound fidelity.
Furthermore, the size of the driver serves as an indicator of sound output. Generally, a larger driver unit correlates with more robust bass delivery. In simple terms, the bigger the unit, the larger the speaker, resulting in a more powerful audio output.
Driver sizes for earbuds
- 8mm to 15 mm
Driver sizes for headphones
- 20mm to 50mm
Types Of Drivers
Dynamic Drivers
This design enables them to excel in delivering powerful bass and achieving high sound pressure levels with minimal power input.
Consumer-grade headphones often employ dynamic drivers due to their affordability and reliability in producing a robust sound signature.
However, it’s important to note that while dynamic drivers offer ample sound output, more doesn’t necessarily equate to superior audio quality; it simply signifies a greater volume of sound.
The HD600 pictured above uses dynamic drivers.
Balanced Armature Drivers
Balanced Armature Drivers in earbuds are compact, precise components that convert electrical signals into sound.
They consist of a coil wrapped around an armature suspended between magnets.
When electrical current passes through the coil, it causes the armature to vibrate, generating sound waves.
These drivers are known for their efficiency in reproducing high-frequency details due to their smaller size and faster response times compared to dynamic drivers.
Balanced armature drivers are often used for delivering clear and accurate audio across the mid to high-frequency range in earbuds, offering a balanced and detailed sound signature.
That said, just because an earbud utilizes a balanced armature design doesn’t necessarily mean it results in a superior sound. The Hidizs MD4 (pictured above) is an example of that.
Planar Magnetic Drivers
They operate on a fundamentally different principle, offering several distinct advantages in audio reproduction.
At the heart of a planar magnetic driver is a thin, lightweight diaphragm suspended between rows of magnets.
This diaphragm is usually made of a flexible material like mylar or a thin film coated with conductive traces.
When an electrical signal passes through these traces, it interacts with the magnetic field generated by the magnets, causing the diaphragm to move back and forth.
This movement generates sound waves, which are then emitted through the headphones.
One of the key benefits of planar magnetic drivers is their ability to produce incredibly detailed and accurate sound across the entire frequency spectrum.
This is because the entire diaphragm is driven uniformly, resulting in minimal distortion and excellent transient response.
Planar Magnetic Driver.
As a result, planar magnetic headphones are often praised for their resolution, imaging, and instrument separation.
Additionally, planar drivers are capable of delivering fast, precise bass response without the distortion commonly associated with dynamic drivers.
This is due to their large, evenly driven diaphragms and the absence of resonant modes that can color the sound.
However, planar magnetic headphones tend to be larger and heavier than their dynamic counterparts (not always, but often), and they typically are less efficient and require more power to drive effectively.
Despite these drawbacks, many audio enthusiasts consider the sonic benefits of planar magnetic technology to be well worth the investment.
I’m certainly a huge proponent of them and recommend planars often.
Overall, planar magnetic drivers offer a compelling alternative for those seeking uncompromising audio performance.
Recap:
- Planar magnetic headphones use a magnetic field around a conductor.
- This conductor has an electrical current flowing through it.
- That electrical current drives the diaphragm.
- Magnets are placed in front of and behind the diaphragm evenly.
- As current passes through the conductors, the magnetic field created by current flow interacts with the field created by the magnets.
- This causes the conductors and the diaphragm to move.
- This produces the sound you hear, and in the case of planar magnetic, a startling lifelike one!
Benefits:
- Sound enters your ears more evenly and naturally.
- Low distortion. The sound isn’t wobbly at higher frequencies.
- Large and powerful diaphragm. The surface area is such that more air is permitted to move with authority. This results in the most powerful and superior bass response out of any headphone.
- Responsive. The diaphragm is light and the force is strong. The ability for the signal to accelerate the diaphragm thus becomes better.
- They are easier to drive from an amplifier. Related: What is a Planar Magnetic Driver?
Tyll’s Anatomy of a Planar Magnetic Headphone Driver
Electrostatic Drivers
Electrostatic drivers are a sophisticated type of transducer used in high-end headphones and speakers, offering unparalleled sound quality and precision.
Unlike dynamic or planar magnetic drivers, which use electromagnetic principles, electrostatic drivers operate on electrostatic principles.
At the core of an electrostatic driver is an ultra-thin diaphragm typically made of a lightweight material like mylar coated with a conductive film.
This diaphragm is suspended between two perforated metal plates, known as stators, which are charged with high voltage.
When an audio signal is applied to the stators, they generate an electric field that interacts with the conductive diaphragm, causing it to move back and forth.
This movement produces sound waves that are incredibly accurate and detailed, with minimal distortion.
One of the key advantages of electrostatic drivers is their ability to reproduce transient details and micro-dynamics with exceptional clarity and precision.
This results in a lifelike and engaging listening experience, particularly for classical and acoustic/folk music genres where subtle nuances are crucial.
Additionally, electrostatic drivers offer a fast response time and low distortion across the entire frequency spectrum, resulting in a remarkably flat frequency response and excellent imaging capabilities.
However, electrostatic headphones require a specialized amplifier called an electrostatic energizer to supply the high voltage needed to drive the stators.
These amplifiers are typically more expensive and less common than traditional headphone amplifiers, which can be a limiting factor for some users.
Despite these requirements, electrostatic headphones are highly regarded by audiophiles for their exceptional sound quality and are often considered the pinnacle of headphone technology.
They represent the ultimate choice for those seeking the most transparent and revealing listening experience possible.
Bone Conduction Drivers
These drivers work by vibrating against the bones of the skull, bypassing the eardrums and directly stimulating the inner ear.
They are often used in specialized headphones designed for people with hearing impairments or for applications where situational awareness is important.
Piezoelectric Drivers
Piezoelectric drivers use the piezoelectric effect to generate sound waves.
When an electrical signal is applied to certain crystals or ceramics, they deform, producing mechanical vibrations that generate sound.
These drivers are often used in ultrasonic applications or certain types of tweeters in speakers.
Magnetostrictive Drivers
Magnetostrictive drivers utilize the magnetostriction effect, where certain materials change shape in response to a magnetic field.
When an electrical signal passes through a magnetostrictive material placed in a magnetic field, it causes the material to expand and contract, creating sound waves.
These drivers are not as common as other types but have been used in specialized applications.
A Dynamic Driver | Image: Earphone DIY Labs
Angled Drivers
These are found in certain high-end headphones like the Beyerdynamic T1 and are angled to give you more of a theater-like presentation.
HIFIMAN headphones also tend to angle their drivers and sound best when the headphones are pushed forward so the back of the earcups are touching the backs of your ears.
- Recommended: 10 HIFIMAN Headphones Ranked From Worst To Best
The sound will start to come at you from the front, as well as all sides, thus improving Soundstage to a degree.
Ultimately, the difference is somewhat small, and they don’t replace true surround sound speakers by any stretch.
Still, open-back headphones with these drivers are known for providing a phenomenal Soundstage, and I can certainly attest to that.
In other words,
you will hear a difference in 3D realism and the resolution may even improve a little.
Examples
Some examples of headphones with Planar magnetic drivers are the Audeze LCD-3, HIFIMAN Ananda/Edition XS, HIFIMAN 400se, etc.
Some examples of headphones that have angled drivers include Sennheiser’s HD800 and the Beyerdynamic T1.
A great entry-level introduction to Planar Magnetic technology is something like the HIFIMAN HE400se.
It’s a superb sound and a definite eye-opening experience with the right equipment.
I remember the first time I heard Led Zeppelin’s Over the Hills and Far Away with the original 400i paired with the Bryston BHA-1.
It was one of the most realistic-sounding tracks I’ve ever heard, and to this day I still remember how lifelike everything was.
It was almost like the track was breathing and had a pulse of its own.
Are YOU ready to delve into the wonderful world of planars and discover how affordable it is to get started?
Learn More:
Well, that’s about it for today my friend! I hope you’ve enjoyed this What Is A Headphone Driver? Discussion, and came away with some valuable insight.
If you love what I do here and want to support the blog and channel in a more personal way, check me out on Patreon and discover all the value I have to offer you.
Questions? Comments? Requests? Did I miss the mark on something? Please let me know down below or Contact me!!
Which of the driver types most piques your interest? I would love to hear from you. Until next time…
All the best and God bless,
-Stu
