Drivers

Dynamic

Most of the time the drivers are dynamic.
This is the moving coil speaker we know for almost hundred years (Rice/Kellogg1924).

 

Sennheiser HD 800

 

Balanced armature

This is a very small driver.

Perfect for a IEM (In Ear Monitor)

 

Etymotic ER3SE IEM with balanced armature

 

 

 

Planar magnetic

This is known as ribbons in the speaker world.


Instead of a coil there is a thin foil hanging close to magnets.
The magnetic field created by the current flowing through the foil makes it move towards or away of the magnets.
As there is quite a gap between foil and magnets, efficiency is in general low.
The magnets make them heavy as well.

 

Audeze LCD X planar magnetic headphone

Electrostatic

Quad ELS was the first commercially successful speaker using the electrostatic principle.


A static loaded foil is moved between two stationary stators depending on the polarity of the stators.
As the foil is loaded, it requires a special amp supplying the bias load ( 300V most of the time)

Stax electrostatic headphone and amp.

AMT

If the former owner of Adams audio starts a new company called HEDD and creates a HEDDhone you expect an Air Motion Transformer, don't you.

 

Heedphone

HEDDphone $1,899

 

 

References
  1. 5 Types Of Headphone Drivers That You Should Know - headphonesty
  2. How Headphone Dynamic Drivers Work - Tyll Hertsens
  3. How Planar Magnetic Headphone Drivers Work - Tyll Hertsens