Headphones and earbuds are basically loudspeakers, only a lot smaller. The key element in both are the drivers. There are two main types of drivers in making earbuds and headphones, balanced armature driver (BA) and Dynamic driver.
BA applications are usually used in professional sectors, such as radio studios, hearing aids and in military applications. Also you would find them in-ear monitors (IEMs), used by audio engineers and musicians as well as audiophiles.
Dynamic driver on the other hand, because of its lower price point, they are widely used in regular headphones, earbuds and also in-ear monitors. Especially used by bassists and drummers thanks to its superior bass response.
There are pros and cons for dynamic and BA drivers. Dynamic drivers are less expensive, and it covers the entire frequency range. However, when it is tuned to deliver say low frequency (heavy bass), mid and high frequency will be sacrificed. Same goes to Mid and High frequency, one goes up, other two goes down.
BA drivers are expensive and usually offers limited frequency range, with weakness in bass and strength in trebles and clarity. To cover full range, multiple (up to 4) BA drivers are often required for performance.
Depending on what kind of music user listens to, dynamic or BA driver each has its strengths. But users might have different tastes of music too, sometimes classical, sometimes R&B and sometimes Pop, it can be annoying to have to switch between headphones/earbuds for listening to different types of music, right?
By combining dynamic and BA drivers, called Hybrid-design, it is now possible to have full range coverage without having to sacrifice any of the low, mid and high frequencies, and best of all it will not cost you a fortune.
For hybrid design, both drivers work together. BA is responsible for mid/high frequencies, such as the vocal part of a song and musical instruments like piano, violin and harp. Yet, when the percussion and bass kick in, the dynamic driver will shift into high gear, much like driving a car at 3000rpm and all of a sudden the turbo wakes up and roars its way in, Hybrid earphones does exactly that! Pretty interesting huh?
Music lovers can now enjoy different types of music with just one pair of earphones!