Why do speakers have multiple drivers, but most headphones don’t?

If you were to take apart headphones and a traditional speaker, you would typically find that the speakers contain more components. Speakers often have multiple drivers, the main components that vibrate to produce the sounds you hear. Headphones have speakers, but they are usually smaller. Most headphones don’t have multiple drivers simply because they are designed to be smaller and portable, and larger drivers and multiple units would not fit or would increase the complexity of the design.

Additionally, larger and multiple drivers may require higher power requirements, which in a portable form factor like headphones would require better battery life, a larger battery, and a bulkier headset. Then there are the associated costs, which vary depending on the format of the pilot. That’s not to say that there aren’t headphones with multiple drivers: many high-end and audio-purist options do, in fact, contain them. For a vast majority of people, single-driver headphones will suffice, but if you dig a little deeper and browse some of the larger headphones favored by audiophiles, you’ll find a plethora of driver options.

There are several types used in modern headphones, including balanced armature, dynamic, hybrid, planar magnetic, and electrostatic. Separately, they produce different sound frequencies, obtained depending on the shape, configuration and size of the speaker. More importantly, a single headphone driver can often handle multiple tones to provide clearer, more balanced sound in a small spatial area, especially dynamic drivers – some of the most common in modern headphones. Other types, such as planar magnetic or electrostatic, offer specialized experiments.

Speakers and headphone drivers are designed the same way. They are made up of individual parts, including a voice coil to receive electrical signals, a magnet to move the system, a diaphragm (a cone or dome) that produces sound waves as it moves, and a suspension system that holds everything together, like a frame. Assembled, the driver takes electrical signals and converts them into sound waves you can hear. Different drivers use different components to achieve this with varying results, but they differ in size, power requirements, and physical capabilities.

A loudspeaker is larger, has a greater surface area to fill, and is intended to serve a larger space, sometimes entire rooms or halls. In comparison, a headphone driver only needs to produce enough sound, or air, for your ears, unless the headphones use bone conduction technology, but that’s another conversation. Most headphone speakers range in size from 20mm to 50mm, while drivers range from half an inch (Tweeters) to 18 inches or more (Woofers).

Bigger speakers need more power, but that’s not a big problem with speakers because you just plug them into an outlet or use an external power source. The headphones are portable, so they rely on batteries, which must be limited to keep the device light and compact. Multiple drivers introduce greater technical complexity. This is why most headphone manufacturers opt for a more efficient system using fewer drivers and with more balanced audio profiles. Small and efficient speakers are also the key to getting compact speakers that sound bigger than your phone.

Most of the features that can ruin the sound quality of your headphones are directly related to the speakers inside and the sound reproduction and accuracy they can achieve. Which type of headset driver is best and whether you should go for a multi-driver headset is a matter of preference. Multi-driver headphones may sound better for someone who cares deeply about their audio quality. The same goes for purchasing different types of headphone drivers, like electrostatic or MEMS.

They have different sound profiles, so the sound will be a little different for each on a basic level. Some people will find that they prefer one type over the other. Dynamic drivers, the most common, are robust, attempt to reach as many frequencies as possible, and require less power, but they do not handle higher frequencies well. Planar magnetic drivers are more precise in terms of balanced reproduction, but they are also heavier and headphones that use them are often more expensive. Electrostatic headphone speakers are also expensive and require a specialized amplifier to power their unique designs, but this extra power and distinct engineering gives them a unique sound response, albeit with less bass.

Finally, balanced armatures are small, efficient, and deliver clear highs with precise sound response, which is why they are used so much in IEMs. However, they also don’t reproduce deep bass, and you’ll almost always want to fine-tune the EQ to find your ideal settings. This is not an exhaustive list, but it can jumpstart your search and should help you better understand the differences between popular driver types.