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Headphone Drivers – Explained

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Ever wondered how your headphones work? And how to make the best possible decision when buying ones? Then it is important to dig deeper and see what drives your headphones. 

What do drivers (transducers) do?

Basically, drivers are units inside the headphones that are in charge of producing the sound. What they do precisely is that they convert electrical signals into sounds. 

A driver is made up of magnet, voice coils, and diaphragm. In short, a magnet creates a magnetic field, voice coils are there to move the diaphragm when an electric current passes through them and diaphragm vibrate in order to produce sound. 

People are known to believe that the bigger the driver unit, the louder and better sound it can produce. However, that is not quite true. It’s the quality of the driver unit that plays a role in how good the sound is. 

Size of a driver unit for earphones is between 8mm and 15mm, while for headphones it goes from 20mm to 50mm. We sometimes believe that bigger is better, but in this case, a bigger driver only means more powerful output, not better output. For example, Apple’s AirPods are very small earphones, but the sound they produce is in range with other amazing brands that make headphones with larger drivers. 

Headphones have bigger drivers because they have the capacity to store them. A bigger diaphragm provides us with better bass sound, but at the same time, these earphones may have problems with producing sounds of higher frequencies. So, never buy headphones just based on the size of their driver unit. Things like the type of driver headphones use, noise cancellation and the frequency range of headphones are far more important when it comes to the quality of the sound.

Both headphone and earphone can have more than one driver unit in them, each of them aimed at generating a different range of frequencies. One driver can produce the sound between 20Hz and 20kHz, but with more than one driver involved, earphones can reproduce different frequencies with minimal distortion. But don’t think that just because earphones have multiple driver units that automatically sound they produce will be better! Well produced single driver headphones will generate better sound than badly made multiple drive headphones.

And if you are wondering what types of driver units exist out there and what are the differences, then keep on reading.

Types of drivers

Dynamic (moving coil) Drivers

The most common type of driver is Dynamic driver since they are the cheapest to produce. Dynamic drivers use larger diaphragms, therefore they are capable of producing more powerful bass and attaining good sound pressure while not consuming much power. 

This driver is built by three main parts and works by using electromagnetic forces:

  1. A neodymium magnet
  2. Voice coil
  3. Suspension
  4. A diaphragm attached to a voice coil

Voice coil becomes electromagnet, thanks to the magnet that magnetizes it. When the voice coil receives current, it creates a magnetic field, which then repels and attracts the voice coil. And since the diaphragm is attached to the voice coil, it also moves and displaces the air around it which results in sound creation.

The larger the air displacement the higher the volume of the sound. Therefore the driver must be able to displace the air in order to reproduce a good bass sound. That is exactly why dynamic drivers are great at creating a realistic bass response.

However, at high volume, the audio is susceptible to distortion, but with well thought out engineering this problem can be solved. 

Some of the earphones that run on these drivers are T20i by RHA and BeSport4 by Optoma.

RHA T20i in-Ear Monitors (Gen. 2): HiFi Noise Isolating Stainless Steel in-Ear Headphones with Remote & Mic
  • RHA's revolutionary Hi-Res DualCoil Dynamic Drivers produce audiophile-quality audio
  • Frequency response - 16 - 40,000Hz
Optoma NuForce BE Sport4 Premium Wireless Sport earphones with mic and 10h battery, sweat proof, AAC + aptX, Quick Charge, Graphene drivers, compatible with Android and iPhone
  • Sweat proof: IPX5 water resistance ensures you're ready for marathons, workouts, intense training sessions, hiking or snow activities without letting rain, snow, Mud or sweat INTERRUPT your playlist
  • Audiophile-quality sound: graphene-coated drivers deliver crystal clear, audiophile sound while AAC and apt support maximize Audio quality for both Apple and Android devices
  • 10 hours of non-stop listening: incredible battery life ensures 10 hours of music playback for non-stop music that endures your training and workouts
  • Charge quickly: forget to charge? A quick 15-minute charge provides 2 hours of listening time
  • Comfortable fit: SPINFIT twin blade ear tips provide maximum comfort, stability and secure fit while interchangeable silicone ear tips and ear wings personalize the fit even further

Balanced Armature Drivers

This is what In-Ear Monitors mostly use. These drivers are very small and in-ear monitors usually contain one to four of them. 

The miniature armature is surrounded by a coil of wire, which is then put between two magnets. This armature is attached to the center of the diaphragm. When the armature is equally distanced from both of magnets, then it is in the state of balance. But, when current flows through the coil, the armature becomes magnetized, forcing it to move towards one of the magnets. While the armature moves, the diaphragm that is connected to it also moves, and as a result, the sound is being produced. 

Since IEMs can have the maximum of four drivers to complete the sound, they can be tuned to cover different frequencies, but their range is still limited. 

One more con to add to this is that Balanced Armature drivers don’t displace air in order to create sound, so there is a lack of bass sound. For this reason, there can be found balanced armature headphones that contain one dynamic driver, so they can achieve producing quality bass sound. On the bright side, because a balanced armature driver does not displace air, they don’t have an additional air vent which provides them with better isolation, and you with better sound.

Earphones that use these drivers are SE535-CL by Shure, and Westone W40

Shure Sound Isolating Triple Driver Earphone with Detachable Cable - Clear (SE535-CL) Triple Flange Sleeves for Compatible Earphones
  • "-CL" designates the product's color variation (clear).
  • Triple high-definition drivers deliver spacious sound and rich bass for cinematic audio in a convenient and portable package.
  • Detachable cable system enables multiple connectivity options for long-term device compatibility, upgrades, and ease of maintenance.
  • Sound Isolating design blocks up to 37 dB of outside noise for immersive listening no matter where you are.
  • Secure, over-the-ear configuration keeps earphones in place and cables out of the way for unmatched, long-wearing comfort.
Westone W40 with Bluetooth Cable Four-Driver True-Fit Earphones with High Definition Silver MMCX Cable
  • TRUE-FIT TECHNOLOGY- 60 years of experience designing products for the ear, has resulted in a universal-fit earpiece that is compact, low-profile, lightweight, and extremely comfortable. Our proprietary eartips enhance the performance of the W40 by ensuring a great fit and seal, right out of the box.
  • BALANCED-ARMATURE DRIVERS- Westone's proprietary balanced-armature drivers provide enhanced sonic detail and frequency range that extends well beyond other in-ear solutions.
  • BLUETOOTH CABLE- Full-resolution Bluetooth Cable uses aptX technology to deliver extraordinary detail, clarity, and a dynamic soundstage that has to be heard to be appreciated. The Westone Bluetooth Cable features; 8 hours of battery life, a 10 meter/ 32 foot range, has a water and dust resistant IPX-4 rating, and features our exclusive MMCX Audio connectors, which allows the Bluetooth Cable to be used with any custom-fit or universal-fit earpiece.
  • HIGH-DEFINITION SILVER MMCX CABLE- Westone's High-Definition Silver MMCX Cable features four strands of low-resistance, pure-silver plated copper alloy, braided around a center strengthening core. Low resistance silver-plated copper wire improves electrical conductivity, providing extraordinary clarity and detailed sound reproduction.
  • IN THE BOX: W40 Universal-Fit Earphones High-Definition Silver MMCX Audio Cable Westone Bluetooth Cable 5 Pair Patented STAR Silicone Tips 5 Pair True-Fit Foam Tips Exchangeable Faceplates Deluxe Zippered Carrying Case 2 Year Limited Warranty

Planar Magnetic Drivers

Here the diaphragm is put between magnets, making very clean and detailed sound without any modifications to it. That is why you can find these drivers in most high-end headphones and earphones. They are more likely to be found in over the ear headphones.

As you may have already guessed, these drivers produce sound thanks to the magnetic field.

The magnets surrounding the diaphragm are both of equal magnetic force. The diaphragm has tinny flat electrical conductors in it. When current flows through those conductors, it creates a magnetic field. Following the laws of physics, this newborn magnetic field causes the conductors inside the diaphragm to move, which then causes the diaphragm itself to move as well, resulting in the creation of sound. 

These magnets are what makes this type of headphones larger and heavier, and also requires more power from the audio source or an external amplifier. 

Regardless, they provide with an excellent, low distortion sound, and great quality bass response, since strong electromagnetic force allows displacement of a large amount of air.

If you are curious about the more in-depth, technical explanation on how these drivers work, then check this article here.

One of the most recent best headphones using this technology are HE400i by HIFIMAN and Audeze LCD-4.

HIFIMAN HE-400I Over Ear Full-size Planar Magnetic Headphones (Renewed)
  • This Certified Refurbished product is tested and certified to look and work like new. The refurbishing process includes functionality testing, basic cleaning, inspection, and repackaging. The product ships with all relevant accessories, a minimum 90-day warranty, and may arrive in a generic box. Only select sellers who maintain a high performance bar may offer Certified Refurbished products on Amazon.com
  • Intended for high performance listening in the home or studio
  • 30 percent lighter than comparable headphones
  • The FocusPad, new beveled hybrid ear pads made of pleather and velour
  • Newly-designed headband with an improved pressure pattern
Audeze LCD-4 Over Ear | Open Back Headphone | Ebony Wood Ring | Leather Ear Pads
  • Acoustically engineered for accuracy The LCD-4 is far and away Audeze's most advanced headphone featuring innovative planar magnetic technology that delivers startling dynamics and incredibly open and spacious sound.
  • Near weightless nano-scale diaphragm The LCD-4 features our most advanced diaphragm design; our exclusive nano-scale film actually weighs less than the air it displaces! Benefits include faster response times for better imaging, and the flattest, deepest, most accurate bass response of any headphone available.
  • Audeze nearly doubles the magnetic driving force Double Fluxor Magnet Arrays focus the magnetic flux to a previously unheard of 1.5 Tesla, nearly doubling the power driving the diaphragm for improved transient response and far greater resolution.
  • Near zero distortion Patented Fluxor Magnet Arrays focus the magnetic flux nearly doubling the power driving the diaphragm for even lower distortion and greater accuracy.
  • Internal soundwaves Patented Fazor Elements guide internal headphone soundwaves to avoid resonance for a more accurate waveform.

Electrostatic Drivers

These can be found in premium headphones, since they are extremely expensive, thanks to its complex driver, and the sound they produce is absolutely breathtaking. Their diaphragms are electrostatically charged, hence the name, electrostatic drivers.

Remember how at planar magnetic drivers the diaphragm was sandwiched between magnets? Well, here it is sandwiched between two electrified plates. The almost massless diaphragm moves between these plates, creating the sound we hear.

Here you can check the amazing explanation of the processes which provides us with one of the best sound experience, as well as headphones powered by this high-end technology.

Conclusion:

And now you are probably wondering which one is the best to choose. There is no doubt that electrostatic headphones would be the best ones, but taking into consideration that most people are budget restrained and that not everyone needs the most accurate frequency and bass response, dynamic drivers seem to be the best fit. However, if you are an audiophile, then going for more expensive, planar magnetic or electrostatic will definitely be worth it.

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