Regardless of it is a headphone, in-ear earplugs or flat-head plugs, the most technical and valuable one and then designer’s most headache is the sound unit. Generally, most of the headphone sound units on the market can be divided into three types, one is dynamic earphone, the other is moving iron earphone, and the third is ring iron earphone. In fact, there is also an electrostatic earphone, but the price is relatively expensive. So it is less used in the market. This article is mainly to briefly discuss the pros and cons of these types of headphone drivers.

The 4 types of Headphone Drivers are:

• Dynamic or moving coil
• Moving Iron (Balanced armature)
• ring iron driver
• Electrostatic

Dynamic:

At present, most headphones are with dynamic driver. The working principle is that when the magnetic field interacts with the permanent magnetic material, the membrane wall will be displaced according to the limit of the current. When the current is positive, it will move to one side, while the negative current will push the speaker membrane to move in the other direction, thereby restoring the sound to the human ear. And if you look carefully at the picture below, you will find that the coil is connected to the diaphragm. This is the characteristic of a moving coil speaker!

Pros:

• the technology is very mature
• Low cost
• The frequency response range is wide: the low frequency of non-in-ear dynamic headphones may be slightly insufficient, while the low frequency of in-ear headphones will be much more abundant. In terms of sound quality, mid-to-high-end dynamic coils have a good dive and a deeper sense of hearing
• Sound field effect:for a good pair of dynamic headphones, the immersive feeling when listening to a song is the most direct manifestation of the excellent sound field, which can give people a good sense of envelopment and atmosphere. As for moving iron earphones, due to its limited volume, the sound field cannot be made very wide, giving people a cold feeling. Whether it is momentum or emotional expression, it is certainly not as good as moving coil earphones

Cons:

• The voice is slack
• The low frequency of non-in-ear dynamic headphones may be slightly insufficient
• Due to the inherent size of the moving coil unit, no matter how small it is, external air is still easy to intervene, resulting in sound leakage.

Moving iron earphones

Inside the moving iron earplugs, the voice coil is wound on a precision connecting rod called “balanced armature” located in the center of the permanent magnetic field. Through this structured precision connecting rod, it is conducted to the center of a miniature diaphragm. This piece of iron vibrates and produces sound under the action of magnetic force. Moving iron earphones cost more due to a late start and technical reasons.

Pros:

• The sound unit of the moving iron is relatively small, which can effectively reduce the space of the ear part and can be put into the deeper ear canal part. Therefore, a soft silicone sleeve has a good sound insulation and anti-leakage effect compared to traditional earplugs.

• The sound of the moving iron unit is very sharp. Its strengths are its resolution, strong sense of speed, instantaneous dynamics and sound density. Everyone who takes pictures pursues high-definition photos. For those of us who listen to songs, we also pursue high-resolution sound quality!

• The frequency response curve of the moving iron unit is flatter, so it is more suitable for HiFi headphones

Cons:

• The sound lacks musicality, most of the tuning is cold, and the emotional and imposing performance is limited
• The frequency space that the moving iron unit can cover is limited, and it cannot have as wide a breadth as a moving coil earphone.
• High-end moving irons require multiple units to be responsible for the response of different frequencies. The addition of frequency division equipment, sound insulation film and other originals naturally increases manufacturing costs.

Ring iron

the ring iron design is to combine the moving coil and the moving iron, and learn from each other’s strengths to achieve a relatively perfect balance. Usually the moving coil unit is responsible for the low frequency part, and the moving iron unit is responsible for the middle and high frequency part. The reason is that the low frequency of the moving coil is more natural, and the low frequency of the moving iron is often too sharp or sharp, so it is not particularly suitable for the moving iron unit to be responsible for the low frequency. However, the design of the ring iron has become more complicated, which is extremely challenging for the tuner. So the ring-iron earphones on the market are great if they are tuned well, and they are almost impossible to listen to if they are badly tuned! And the earphones of the ring iron design are not cheap!

Electrostatic earphones

The diaphragm is in a changing electric field, and the diaphragm is extremely thin, accurate to a few microns, and the coil drives the diaphragm to sound under the drive of the electric field force. Due to the very high manufacturing cost, electrostatic headphones have always been a relatively niche product. The principle is to amplify the audio signal and connect it to a fixed pole plate, and the changing audio signal will produce a changing electric field between the two pole plates. The metal diaphragm of the earphone is located between the two pole plates, and a very high voltage is connected to the external. The electric charge on the diaphragm is forced by the changing electric field generated by the audio signal, so that the diaphragm oscillates to form sound

Pros:

• The diaphragm of the electrostatic earphone is made extremely thin and light.The lighter and thinner diaphragm of electrostatic earphones brings faster speed, better transient response, stronger detail expression, and extremely low distortion.

• The electric field received by electrostatic headphones is completely uniform.The diaphragm of an electrostatic earphone is a completely flat diaphragm sandwiched between positive and negative two.parallel fixed pole plates, and the electric field received is completely uniform. So it can achieve linear drive, there is no split vibration, this limitation of moving coil earphones is not at all.

• Electrostatic headphones can control the minimum point of the diaphragm. The smallest point at which electrostatic earphones can control the diaphragm is much smaller than dynamic earphones. An analogy with the resolution of the monitor is: On the same size display, the resolution of electrostatic headphones is 1024 by 768. And dynamic headphones can only reach 800 by 600.The sound composed of smaller points is more delicate and precise.

Cons:

• Very Expensive
• Electrostatic headphones have high electrostatic technology content and high cost
• The technology of the pronunciation unit of electrostatic headphones is only in the hands of a few companies

Conclusion:

While the final choice may come down to cost and availability, it is still worth knowing all the facts before you make your final headphone choice.

For the most part, the dynamic driver is the first-rate purchase for effectiveness and price, but there are circumstances where the other drivers may be more useful for your needs.