To this date, there are currently 3 categories of headphones available on the market. This article will help you filter out the category that you would be most interested in.
The categories are:
2) Ortho-dynamic/Iso-dynamic Headphones
3) Electrostatic Headphones
The three categories are based on the type of technology used to produce sound from the headphones. The difference is the type of transducer principle to convert electrical signals into sound waves.
1) Dynamic Headphones
Dynamic headphones are using a moving coil driver. A moving coil driver simply means that there is a magnet in the headphone, which produces a static magnetic field. A voice coil attached to a diaphragm is placed in the magnetic field and a current is run through the voice coil making it cause the diaphragm to vibrate and produce sound waves.
Most dynamic headphones need little electricity for it to work. Due to this, the majority of headphones on the market are dynamic headphones. Average music listeners, musicians and professional studio mixers use them. The most popular manufacturers in the music industry that produce dynamic headphones, includine Sony, Beyer, Sennheiser, Grado and Audio-Technica. They can cost $8 or $800 US Dollars (USD) upwards and can be wired or wireless, open-air or closed-back, ear buds or studio-quality.
Pros of dynamic headphones are that they are widely available and are usually cheaper that ortho-dynamic and electrostatic ones. Since little electricity is needed to drive them, most of them will work with portable devices and computers without a need of a headphone amp. A headphone amp is a miniaturized power amplifier specifically designed to drive the tiny speakers inside the headphones.
The cons are that orthodynamic and electrostatic headphones can beat them in terms of speed and clarity.
Dynamic headphones are the best headphones to start with due to their cost and wide range.
2) Orthodynamic / Isodynamic Headphones
Orthodynamic headphones were very popular worldwide in the 1970s. Some consider them old technology but have a revival now.
Manufacturers include Audeze, Fostex, Hifiman, Kenwood and Dual.
Orthodynamic headphones have flat and bigger voice coils, which cover the diaphragm. This means that the current is better distributed to the diaphragm, which in turn produces sound waves. Bigger voice coils mean bigger diaphragms (even bigger than electrostatic headphones) and that means that more electricity is needed to drive them.
Pros of Orthodynamic headphones are that they give excellent response and sound quality similar to that of an electrostatic.
Cons of Orthodynamic headphones are that they are generally bigger and require a headphone amp to drive them thus they are not portable. They are also generally more expensive than dynamic headphones.
3) Electrostatic Headphones
Electrostatic headphones have drivers, which do not have a voice coil. The diaphragm is instead charged with electricity. The diaphragm is placed in between two electrically charged metal plates (electrodes), which are perforated. When the diaphragm vibrates, air is forced through the perforated metal plates producing a sound wave.
Electrostatic headphones are usually more expensive than dynamic headphones, and are comparatively uncommon. Due to the diaphragm and two metal plates, which are needed to be charged with electricity, the headphones need a big amount of electricity to drive. The amount is so much that normal amps which drive dynamic and/or ortho-dynamic headphones just won’t cut it. A special headphone amplifier is needed which often requires electrical potentials in the range of 100 to 1000 volts.
The thin diaphragm that is only a few micrometers thick allows it to produce a frequency response, which extends well above the audible limit of approximately 20 kHz. In other words, they produce higher clarity and sound quality.
Akg and Stax produce electrostatic headphones.
Pros of electrostatic headphones are the sound quality and clarity.
Cons of electrostatic headphones are that they are expensive, require the owner to purchase a special amp to drive them and they lack bass. There is lack of slam / impact compared to dynamic headphones.
Most experts agree electrostatic phones can actually produce a higher-quality sound than dynamic headphones. The reason they aren’t more popular is that they are far more expensive, starting at roughly $1,000 USD and reaching to nearly $15,000 USD for the industry’s best.