Understanding Headphones Driver
The driver is the most important unit in headphones. That’s because it’s the component that converts electrical signals into sound. In other words, it creates the sound you hear. Think of headphone drivers as tiny loudspeakers inside your ear. A driver unit is composed of three components:
Magnet – generates a magnetic field that can affect the overall sound quality of the headphoneVoice coils – Moves the diaphragm to create the sound you hear when an electric current passes through themDiaphragm – vibrates to create sound waves that human ears can pick up
A headphone driver is disc-shaped, and the size varies depending on the make and required sound output.
The Impact of Driver Size on the Audio Quality
In simple terms, the larger the driver the better the bass. But that doesn’t always mean headphones with larger drivers produce better sound than their counterparts with smaller drivers. Far from it. There are many factors that come into play when it comes to headphones’ sound quality. Here’s everything you need to know about how driver size impacts the audio quality.
Is Bigger Always Better?
A standard earphones driver is usually in the range of 8mm to 15mm in diameter while a headphones driver ranges from 20mm to 50mm in diameter. Generally, a driver’s size determines the loudness of the headphones. Many believe the bigger the size, the better the sound quality. This is not entirely true, although due to a larger diaphragm, the bass may be a little cleaner. However, headphones with large drivers also tend to struggle in reproducing high frequencies (treble). While bigger drivers are capable of producing higher output, this doesn’t mean they deliver overall better output. It’s the quality of the driver unit and the variation of materials inside that makes a huge difference. Take Google’s Pixel Buds or any other tiny earbuds, for example. These earbuds are quite small with very small drivers, yet they produce sound quality that rivals other brands with larger drivers. Also, we can learn a thing or two from Audio Technica. This company makes two high-end headphones models: the M40X and the M50X. The M40 uses 40mm drivers while the M50 uses 45mm drivers. You’d assume that the M50X produces better sound due to its larger drivers, right? Not necessarily. Both headphones are tuned very differently. The M50X has tuning, pads, and enclosures designed for a slightly aggressive response, while the M40X is designed around a flatter and more neutral signature. In both cases the type of padding used and the enclosure of the cups have a larger impact on the sound than the drivers used. In a nutshell, the size of the driver does affect the output and the frequency range of headphones. However, you should not base your buying decision on the size of the drivers alone. There are other factors, such as the type of drivers used and the frequency range that affects the quality of sound more than the size of the drivers used.
Does Having Multiple Drivers Equate With Better Sound Quality?
The short answer is – not necessarily. Just as with driver size, having multiple drivers (per side) on board a pair of headphones does not absolutely guarantee better sound. Multiple driver headphones use each driver to manage a specific range of frequencies including audio bass, mids, treble, etc. Even on paper, that should be enough to get improved sound quality. In practice, a poorly produced multi-driver unit will always perform worse than a high-end single driver. As driver technology has become more capable in recent times and our understanding of headphone sound tuning has improved, using multiple drivers is no longer an absolute necessity. So it’s indeed possible to get better sound from headphones featuring a single type of driver.
Different Types of Headphones Driver Units Explained
As mentioned earlier, the type of driver used in earphones greatly affects the quality of sound. Here are the various types of drivers commonly used in earphones and headphones.
1. Dynamic (Moving Coil) Drivers
Dynamic drivers boast the most simple configuration of all driver types that we are discussing here. They use a magnet, typically a neodymium, whose magnetic field interacts with the voice coil. With current coursing through it, the voice coil begins to oscillate, prompting the diaphragm to do so as well following the same rhythm. This oscillation of the diaphragm moves air in front, producing sound waves. If you’re looking for headsets that deliver a thick bass punch, go for the ones with dynamic drivers. These drivers are very common in headphones and feature a larger diaphragm. They do a stellar job in delivering powerful bass and attaining good sound pressure without consuming much power. Despite dynamic drivers being highly effective, one of the biggest complaints against them is that they can produce harmonic distortion at louder volumes. Fortunately, the effect can be countered by good engineering. Dynamic drivers are usually the norm when it comes to lower-end, cheaper headphones, but they are also often used in higher-end models such as the Sennheiser HD 660 S, as well.
2. Planar Magnetic Drivers
These are the driver types you’ll find in most of the high-end headphones on the market today. While usually found in open-back, over-ear headphones, in-ear models are also available of late. With this tech, a diaphragm is sandwiched between magnets. Similar to dynamic drivers, planar magnetic drivers operate using a magnetic field. But rather than making use of a coil, the diaphragm (thin flat film) in these drivers becomes directly affected by the magnetic field and so, creates sound. Additional magnets are employed so that the whole diaphragm can vibrate evenly. This adds a bit more weight to the headphones. It also means the headphones will need more power from the audio source or from an external amplifier. Therefore, planar magnetic driver headphones are mostly made for home use. However, companies like OPPO have innovated in this area this area with their PM series of headphones that are more lightweight and geared toward portable use. These drivers produce very accurate and clean sound, giving you every bit of detail without adding too many sound effects or other modifications. For this reason they are the go-to choice for audiophiles. You’ll find them in most of the high-end headphones such as the Audeze LCD-5.
3. Balanced Armature Drivers
These are very small drivers, and their typical use is with in-ear monitors. Due to their size, manufacturers will put multiple drivers in a single earpiece. Typically, most in-ear monitors come with one to four drivers. Using more drivers in a single earpiece allows these earphones to reproduce different frequencies with minimal distortions. Bass notes are usually handled by an individual driver, while the rest are dealt with by the remaining ones. This type of driver consists of a coil wrapped around a miniature arm (armature). Two magnets flank the armature, and by interacting with the magnetic field created by the current passing through the coil, they set the armature in oscillatory motion. Since the diaphragm is connected to the armature, it will move synchronously with the latter, thus producing sound waves. When the armature becomes centered within the magnetic field, there’s no net force applied on the armature, which gives it its “balanced armature” name. One major downside of balanced armature drivers compared with dynamic ones is that they have difficulty reproducing the bass response. This is why it’s not uncommon for some in-ear monitors to include multiple balance armature drivers and a dynamic one, as the latter makes up for the lack of bass response. One such product is the 1More Triple Driver In-Ear headphones. On the upside, in-ear monitors using balanced armature drivers usually tend to offer better isolation for an extremely detailed sound experience.
4. Electrostatic Drivers
These are rare and extremely expensive. Electrostatic drivers operate based on the fact that – like charges, they repel each other while opposite ones attract. Vibrations are produced as the diaphragm pushes and pulls against two conductive plates (that may be positively or negatively charged) or two electrodes. The air is then pushed by the diaphragm through the perforated walls, and together with the continuous variation of the electrical signal, it creates sound waves. These are drivers that require special amplifiers to perform to their full potential. Thus, you’ll find this type of driver in high-end headphones that usually sport an open-back design. They produce exceptional sound quality with breathtaking accuracy. For this reason they come with a hefty price tag and are only found in premium headsets like the STAX SR-007 MK2 model.
5. Piezoelectric Drivers
Not to be confused with electrostatic drivers, piezoelectric ones are a unique type of drivers that have made it into some modern hybrid headphone models such as the BQEYZ Summer. These drivers work by applying voltage to piezoelectric material which is usually crystal or ceramic in order to move the diaphragm. Electricity is what alters the physical form of these materials, resulting in the movements that make the diaphragm vibrate. What’s great about these types of drivers is that they are capable of converting even the weakest audio signal into sound. On the other hand, manufacturers can do only limited fine-tuning of these drivers, due to the nature of the piezoelectric materials. This can result in low-quality sound, and large power consumption.
6. Bone Conduction Drivers
These drivers are capable of transferring vibrations directly to the user’s inner ear (bypassing the eardrum) via bone conduction. Headphones using this type of driver target individuals who need to use headphones in mediums where they still need to hear environmental noises or suffer from hearing problems. However, with bone conduction drivers, you’ll certainly be trading usability for quality. Right now this category is no match for the other types of drivers when it comes to delivering high class sound. Image credit: Pexels But if you intend to use the headphones solely for gaming, you most likely won’t care much about the bass or the mid-lows. Go for the ones with balanced armature drivers. On the other hand, if you usually listen to music while out and about, you may want to look at models with bone conducting drivers. If you’re an audiophile, you probably don’t need our advice on what headsets to buy, do you? I’ll say it anyway. Go for planar magnetic drivers. And if budget is not a constraint, headphones with electrostatic drivers will satisfy your curiosity more.
