Shopping around for headphones is confusing enough as is, and there are a lot of things you need to keep straight. Should you get on-ear headphones or in-ears? Open back or closed back? Is Bluetooth better or wired? While there’s plenty of reading to do on those questions, we’re here to give you a quick and easy breakdown of four different driver types: dynamic, planar magnetic, electrostatic, and balanced armature.
Editor’s note: this article was updated on February 22, 2021, to expand upon technical details.
What is a headphone driver?
Before we start walking, we have to learn to crawl. As the name suggests, a driver is a raw speaker that drives the air. This movement creates pressure waves, resulting in sound into your ear canal. It’s a component that converts electrical energy into acoustic energy, also known as a transducer, or sometimes a motor. A driver serves the core function of loudspeakers and headphones, and it produces the sound you hear. And as the varying sizes of headphones and IEMs show, drivers also differ in size considerably.
- Most affordable driver type
- Compact and lightweight
- Fairly robust
- Not the best in terms of sound reproduction
More often than not, dynamic drivers are found in consumer-oriented headphones. Why? Simply because they’re an affordable choice. A fixed magnet—typically neodymium—creates a static magnetic field. This interacts with the electrical current in the voice coil which is subsequently forced to move back and forth with the applied signal. The voice coil is attached to a membrane, or diaphragm, which acoustically amplifies vibrations and, thus, sound waves are produced.
How do dynamic drivers affect my music?
Although the basic moving coil concept hasn’t changed much in close to 100 years, it has been refined considerably. Dynamic drivers will however be prone to limited bandwidth due to resonances, power compression, and other forms of distortion.
Variations in dynamic driver sound quality can be attributed to different materials used and the compromises made in the design.
Though they’re generally the worst-performing drivers discussed in the article, the truth is they’re not bad—but better sound quality can be found if you’re willing to spend.
Planar magnetic drivers
- Lower distortion
- More accurate sound reproduction
- More expensive
- Headphones with planar magnetic drivers tend to be heavier than those with dynamic drivers
Headphones that use planar magnetic drivers sport a distinct look: the inside of the ear cups features a rectangular—rather than elliptical opening. Although planar magnetic drivers are typically found in open-back, over-ear headphones, we’re seeing an uptick of in-ears using them too. Some manufacturers use their own names for headphones using this technology: “magneplanar,” “isodynamic,” or “orthodynamic,” all refer to planar magnetic headphones.
The basic principle of operation for planar magnetic drivers is the same as the dynamic driver: an electrical conductor moves between fixed magnets as an audio signal is passed through it. Rather than a coil attached to to a conical diaphragm, the a planar magnetic driver’s conductor is laid out in a 2D pattern and attached to, or embedded in, a film-like diaphragm that can be made extremely flat. Multiple magnets are laid out on both sides of this diaphragm, producing a uniform magnetic field, where it stays.
Audeze’s planar magnetic headphones use proprietary magnets to create a magnetic field. Due to the more complex structure of the motor system and large diaphragm, these models often cost more, are heavier, and less efficient, meaning they require more power to be driven. In other words, Audeze planar magnetic headphones typically need an amplifier.
How do planar magnetic drivers affect my music?
Because the large, flat diaphragm moves in unison, and is well controlled, some of the issues with the moving coil design that cause distortion are avoided. This driver design improves phase response too, by creating what’s called a “planar wavefront” (a flat source of sound). This helps present a more detailed, more coherent representation of the music.
- High sensitivity
- Accurate sound
- Specialized amplifier required
- Bulky and heavy headphones
Electrostatics operate on a completely different principle than than the conventional dynamic technologies discussed so far. They work by applying a static electrical charge to a thin film which floats between two perforated metal plates; when audio signals are applied across the plates, the entire film membrane moves back and forth due to electrical attraction and repulsion. It’s the same principle as condenser microphones use to capture sounds, but in reverse.
Headphones that use electrostatic drivers are much more expensive than your standard dynamic driver and require a specialized amplifier, only increasing the overall cost.
How do electrostatic drivers affect my music?
Because the thin film diaphragm has no resonances or energy storage, it is free of the distortion inherent in moving coil speakers. While this accuracy is much sought after, it’s not realistic to produce on a grand scale for general consumers. The sheer expense and the fact that they require bespoke amplifiers to even work means that these are the domain of enthusiasts only.
Balanced armature drivers
- Smaller and more efficient than dynamic drivers
- Excellent treble response
- Can delegate range of frequencies to each armature (if multiple armature IEM)
- More expensive than dynamic drivers
Balanced armature drivers are much smaller than the others listed and their main application is in-ears and hearing aids. As with the others, the name gives an idea how balanced armature drivers work. A magnetic armature rests on a pivot and rotates between two magnets. When it’s centered within the magnetic field, there’s “no net force on the armature.” In other words, it’s at this point that the armature is balanced.
When an electric current is sent through the coil, which is wrapped around the armature, the magnetic force makes the armature move. This motion causes the diaphragm to move and create sound waves.
How do balanced armature drivers affect my music?
Although it requires quite a bit of force for the armature to remain in the balanced position, it’s still a fairly efficient process. Some headphones, like the 1MORE Triple-Driver In-ear, use multiple armature drivers.
Doing so delegates certain range of frequencies to each armature—bass notes will usually be handled by an individual driver, and the rest will be handled by one to three others, allowing drivers tailored to each frequency band to be used.
Which driver type is the best?
As with all things, you have to make a cost-benefit analysis. Sure, you could blindly say that electrostatic drivers are “best,” but that would be a gross oversimplification. Assuming that most of us operate within constrained budgets and don’t need the most accurate frequency response, dynamic drivers do make the most sense. They’re cost-effective and pretty robust. Whether you want something cheap and functional or luxurious and analytical, dynamic drivers have you covered.
Of course, if audio is your passion and you have the means to pursue that passion, planar magnetic, electrostatic, and balanced armature-driven headphones are worthy upgrades. Although these driver types require a bit more shopping around, there are plenty of options out there. And as demonstrated by the Monoprice Monolith 1060, not all planar magnetic headphones have to set you back thousands of dollars.
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