The difference between Planar Magnetic and Electrostatic headphones all have to do with their specific driver technologies, and how those work to produce sound.
Essentially, electrostatic headphones use quickly alternating electrical charges to push and pull a thin diaphragm at rapid speeds, thus moving the air around this diaphragm and producing sound.
Planar Magnetic headphones use opposing sets of magnets on either side of the diaphragm, which will generate its own opposing magnetic field, thus causing the oscillating movement and achieving the same result.
The results have different effects on the listening quality, and even though these types of headphones are often considered more high end than typical dynamic drivers, it’s hard to conclusively say they are better or worse. As with anything, it depends on your preferences and what you want out of your headphones.
To understand these differences, first it makes sense to go over a standard dynamic driver.
This is easily the most common type of driver and its based reliable technology we’ve been using since roughly the 1800s.
The essential components are a magnet, a voice coil and a diaphragm. The magnet creates a magnetic field, and when the voice coil has a current passed through it, it will react to that magnetic field and move. The voice coil is attached to the diaphragm, which is the cone portion you can usually see on a loudspeaker, and the oscillating motion of this cone back in forth disrupts the air around it - which is what produces the actual soundwaves.
That’s essentially the operating principle of any headphone driver - moving air which in turn creates sound. These other types of drivers achieve the same result, but a little differently.
In an electrostatic headphone, the driver consists of just an extremely thin diaphragm that sits in between two perforated metal plates. This diaphragm holds a constant electrical charge, thanks to a conductive coating that covers it. The membrane is locked into place with what are called spars, with just enough room to oscillate back and forth freely.
Now here’s how the real magic happens. One of the metal plates will have the same charge as the diaphragm, and one will have the opposite. The diaphragm will be pushed away by the plate with the same charge, and pulled toward the one with opposite charge. When an audio signal is sent into the headphone, the signal of these metal plates switches back and forth at a very fast rate, causing the diaphragm to oscillate and move the air around it, which in turn produces your sound.
There are a lot of benefits to these types of drivers over the traditional dynamic driver. For one, electrostatic drivers offer high levels of accuracy and remarkably low distortion due to the simplicity of the mechanic. Instead of many components stuck together with adhesive, it is one very thin component that is moving extremely efficiently.
Because of the very small size and light weight, these are also very fast and sensitive, which means transient responses are very tight and exact. This makes all your bass and low end very tight and controlled.
However, as you might imagine these require specialty amplifiers to generate all this power, and in general electrostatic headphones are way more expensive than their more standard counterparts. They are often not very realistic for the vast majority of consumers.
Planar Magnetic Headphones
Planar magnetic headphones use very similar technology, but also have a few different operating principles that kind of bridge the gap between these first two driver types.
A planar magnetic driver consists once again of a diaphragm, but this time that diaphragm contains an embedded wire pattern, very similar to the voice coil you find in a traditional dynamic driver. This diaphragm is suspended between two sets of permanent, oppositely aligned, magnets. These magnets are cut and spaced precisely - thus magnets along a plane, ie planar magnetic- so that the driver is held perfectly in place between those magnetic fields.
A current passed through the wire embedded in the diaphragm produces a magnetic field that reacts with the field of the permanent magnets on either side of the headphone, which creates that undulating movement in the diaphragm, thus producing your sound.
Because these are very similar to electrostatic headphones, they have a lot of the same benefits, including the high speed, sensitivity and transient response. However, these perform even better in the low end department. Because of the superior strength of magnetic force over static electricity, planar magnetic diaphragm can move with a lot more power and slam, offering probably the best bass response of the bunch.
Planars also have a much lower impedance than electrostatic headphones due to the embedded voice coil pattern on the diaphragm, which makes it much easier to drive and therefore less expensive.
The shape of planar magnetic and electrostatic drivers provides a big advantage over the traditional dynamic driver. The cone shape of the latter produces a more spherical wavefront, which means that there is a lag between air being pushed by the rim and the center, the delay of which is a small but discernible form of distortion. The much more even air displacement by planars and electrostatics offers an advantage here, and leads to overall performance in areas of transient response, as well as soundstage.
Hifiman Ananda ($699.00)
This is a really nice Planar Magnetic unit that sits at a very reasonable median price. Hifiman is a brand that makes some great planar magnetic headphones. These have a superb amount of detail, a pretty neutral sound signature, and great dynamic performance which makes them very musical and nice to listen to.
Sivga PII ($399.00)
This is another even more affordable planar option. Sivga is a great company that makes a lot of very cool looking wooden headphones, and these are made of walnut. They have a low impedance of 32 ohms, so they are very easy to drive even with the pretty huge 96mm driver. These cans are really well balanced but also have a good rich warmth to them, and the imaging and layering are really outstanding here.
Stax SR L700MK2 ($1,569.00)
This is one of the classic brands and models that many people will turn to when they are ready to level up to electrostatic headphones. These offer sublime levels detail, almost to an ethereal degree, and the presentation is smooth and just at a really high level you won’t get with much else.
You may find our "Planar Magnetic vs Electrostatic Headphones Explained" video review helpful as well. Watch it below.