There are a variety of different drivers used in over-ear headphones, each with their own unique characteristics. The two most common types of drivers in headphones are dynamic and planar magnetic. Dynamic drivers have been around since 1924 and are by far the most commonly used type of driver for both headphones and loudspeakers. If you ever took a pair of headphones or a speaker cabinet apart just for fun, it almost certainly had the large magnet and paper cone of a dynamic driver. Planar magnetic drivers have some really strong characteristics for headphones, and have been gaining popularity in the audiophile world since their introduction in the 1970s.
While those are the two most common, there are three other types of drivers that are worth covering: electrostatic, ribbon, and air motion transformer. Electrostatic drivers were first introduced in loudspeakers in the 1950s, and while they often require specialized equipment to enjoy, have maintained a following since their introduction. Ribbon drivers are actually just as old as dynamic drivers, also having been invented in 1924, but never found the level of popularity in the market. The air motion transformer is probably the least common of any the drivers mentioned, and up until very recently has primarily been used for tweeters in high-end loudspeakers.
Driver Basics
While there are a number of different variations on the technology, essentially all driver types have four key parts: the diaphragm, magnet, coil, and suspension. The diaphragm is the part that moves, the coil and magnet transmit the electromagnetic signal into the diaphragm, and the suspension is where the diaphragm is seated. When you plug your headphones in to your source, a wire carries the signal into the coil, the coil transmits the energy into the diaphragm, and the diaphragm moves within the suspension to generate a sound.
If you want to read an in depth technical explanation of how different driver types work, along with a detailed history of them, Wikipedia has a number of riveting entries covering the scientific principles of electromagnetic transducers. We’re going to be a little lighter on the science, and a little heavier on the practical aspects of buying headphones and listening to music with different types of drivers.
Outside of the technical details, there are a few criteria that we can use to compare different headphones and driver types. Transient response or speed refers to how quickly a driver can respond to and deliver the information it’s being given. A faster response means a more accurate reproduction of the sound and less feeling of congestion or muddiness. Another aspect is whether or not the instruments sound natural. Ideally, the instruments as reproduced in the music sound just like a real instrument in the room with you, however, sometimes, instruments take on a “tinny” or “metallic” sound.
Some drivers are better at reproducing certain frequencies than others, particularly when it comes to low-end frequencies. Along with that, the motion of the driver can “move air” to generate a physical sensation, enabling you to feel the music as much as hearing it. In most cases, those physical sensations are considered a positive aspect of the driver performance, helping to further immerse you in the music.
Dynamic Drivers
If you’ve spent any time in the world of speakers or headphones, you’re probably familiar with the traditional speaker design: a magnet with two wires connected to it and a paper cone diaphragm around it. Sound is created by the electrical current causing the paper to vibrate at the correct frequency to reproduce a sound. Dynamic drivers are very common, and while the vast majority of inexpensive headphones use dynamic drivers, there are also a number of premium, top of the line dynamic headphones from companies like Focal, Sennheiser, and Audio-Technica that deliver incredible performance.
Dynamic drivers are solid all around performers, which tend to be easier to drive and less sensitive or fragile that other driver types. By design they generate a lot of motion and push a large amount of air around, which results in more natural sound reproduction than other driver types, and provides a good degree of physical responsiveness. Of course, the high levels of motion makes it difficult to get high levels of speed from the drivers while the driver is also making large movements, which can create distortion. However, dynamic drivers using the highest grade of materials and design, like the Beryllium drivers in the Focal Utopia, can provide both the speed and lifelike response, but not without a price.
Advantages
- Typically less expensive than planar magnetic drivers
- Generally easier to power than other driver types
- Great physical impact
- Natural sound
- Excellent reproduction of the full frequency range
Disadvantages
- Don’t have the same level of speed as Planar or Electrostatic
- More prone to harmonic distortion
Dynamic Driver Headphone Picks
If you want a demonstration of dynamic drivers’ ability to generate powerful physical bass in a headphone, the Meze 99 Classics will give it to you.
For the ultimate in dynamic driver performance, the Utopia delivers the full frequency spectrum, with every ounce of microdetail and texture you can wring out of a recording.
Planar Magnetic Drivers
Planar Magnetic drivers are far less common than dynamic drivers in mainstream consumer products, but many of the best and most popular audiophile headphones use them. Planar magnetic drivers have a thin flat diaphragm with a wire running through it. The magnet is suspended next to the diaphragm. The electromagnetic signal running through the wires moves the diaphragm by turning it on and off to create the reaction between the magnets and the diaphragm. Planar magnetic drivers are more sensitive than dynamic and require greater precision in production. They also tend to be larger than dynamic drivers, resulting in very large headphones and less portability.
Planar magnetic drivers have a faster and more uniform motion than dynamic which typically creates a faster transient response, and creates a different sort of physical slam than dynamic drivers. The design is also less prone to harmonic distortion. While most dynamic headphones can be sufficiently powered by the integrated amps in common devices, planar magnetic headphones typically require some level of additional power from a headphone amp to meet their full potential.
Advantages
- Faster transient response than dynamic drivers
- Less prone to harmonic distortion
- Different sort of physical response than dynamic but can be equally impactful
- Excellent reproduction of the full audible frequency spectrum
- Great all around drivers with a balance of characteristics of dynamic and electrostatic
Disadvantages
- More difficult to drive than dynamic drivers
- Accidental damage more likely to impact the driver’s performance
- Generally larger than dynamic headphones
Planar Magnetic Headphone Picks
Sundara is quite possibly the most popular audiophile planar magnetic headphone , and for good reason. You get a taste of the detail, speed, and accuracy that planar magnetic drivers can provide at an affordable price.
The Meze Empyrean is the flagship headphone for listeners who want warmth and musicality rather than a more analytical sound. It provides the detail and resolution of a top of the line headphone, with an addictive, accessible sound.
Other Driver Types
Electrostatic Drivers
Electrostatic drivers are often considered the third major headphone driver technology. The basics of the design are somewhat similar to planar magnetic drivers, but rather than using a diaphragm with a wire, the diaphragm is moved by static electricity. Using this technique there is virtually no movement in the diaphragm as it generates the sound, which enables it to have incredibly accurate sound reproduction and incredible speed.
There are two key disadvantages to electrostatic drivers though. One is that they require a fairly large and heavy “energizer” in order work. Those energizers can also produce high enough voltage levels that some manufacturers have included warnings to not disconnect the headphones while the energizer is on to prevent shock. The other disadvantage is that electrostatic drivers can’t produce low frequencies as effectively as dynamic or planar drivers, resulting in less bass.
Because of the need for a specialized energizer, many electrostatic headphones are sold as sets with an energizer matched to the specific headphones. One example of this is the HIFIMAN Jade. The Jade provides a very high level of performance for the price, compared to planar magnetic drivers, but with the already noted cons of a complicated setup, and lower level of bass response.
Ribbon Drivers
Ribbon drivers are named as such because they use a long thin diaphragm which is coated in a conductive material that looks like a ribbon. Like electrostatic drivers, ribbon drivers produce very little movement, and so have incredibly fast transient response and accuracy. Ribbon drivers are most commonly used as tweeters, covering the treble range for a loudspeaker. If you’ve read this far, you may have guessed that ribbon drivers also tend to have a hard time reproducing low end frequencies, and create less of a feeling of impact.
The premier ribbon driver headphone is the RAAL-requisite SR1a. It is known for its incredible, fast, accurate, detailed sound. Like electrostatic headphones, the SR1a has specialized amplification needs, creating a similarly sized footprint.
Air Motion Transformer
Air motion transformers (AMT) use a similar design to ribbon speakers, with the diaphragm and conductor being one long, thin material. However, the one key difference is that the AMT design generates sound from both sides of the driver, not just the front. Again, the AMT is primarily used for tweeters in loudspeaker systems, and is fast and accurate, but doesn’t have the same level of bass response. AMT drivers, in spite of their high level of technical performance, don’t have the same sort of natural response as most of the other driver types. One thing that makes AMT drivers perhaps more promising for headphones is that they don’t require any specialized amplification, and have similar power requirements as planar magnetic drivers.
There is currently only one over-ear headphone on the market that uses AMT drivers, the HEDDphone. The HEDDphone provides an incredible level of detail and a huge soundstage, with pinpoint imaging.
So, What’s the Best Driver for Me?
There’s a lot of information out there about the technical and performance differences between different types of headphones, but that doesn’t necessarily cover what’s going to work best for you. If you’re primarily sitting and listening at a desk, at home, with no concerns for mobility or anything else, you’ve pretty much got a world of options: depending on your preference for bass, speed, other factors, just about any headphone could work for you. If you’re listening on the go, or at work, an easy to drive dynamic headphone might be the best bet, or a planar magnetic paired with a portable amp. Ultimately the best type of headphone driver is the one that matches the sort of sound you like, and best fits into your lifestyle.
