Some theories about headphones

This article uses my own opinions to introduce to you some theories about headphones and sound quality. Pure theoretical content will be relatively boring to read. The content nodes are as follows.

  • Sound unit type
  • The relationship between sound unit size and sound quality
  • What is graphene diaphragm
  • Term describing sound quality
  • How to use headphones reasonably   

Sound unit type

What is a sound generating unit? To simply understand, it is a component that converts electrical signals into sound. In vernacular, it is a speaker. In headphones, it is a miniature speaker. The main components of the sound-generating unit are magnets, voice coils, and diaphragms.

There are several types of sound-generating units based on different structures and materials: moving coil units, moving iron units, planar diaphragm units, and electrostatic units.

1. Moving coil unit

The more common headphone sound unit consists of a set of magnets, a voice coil, and a conical diaphragm. The principle is that when current passes through the voice coil, a magnetic field is generated and interacts with the magnet next to the voice coil, thereby pushing the diaphragm to vibrate.

2. Moving iron unit

The sound generation principle is similar to that of a dynamic unit, except that the position of the voice coil and the internal structure are different. The voice coil is wound around a balanced armature in the center of the permanent magnetic field, and the magnetic force causes the armature to drive the diaphragm to produce sound.

3. Planar diaphragm unit

The diaphragm is located between the magnets and is clamped by the magnets, so the sound is accurate, clean and crisp.

4. Electrostatic unit

Using a statically charged diaphragm to produce sound requires extremely high precision in the internal structure and is expensive.

Among the four types of sound generating units, the most common ones are moving coil units and moving iron units. Moving iron units are often used in in-ear headphones. They have higher sensitivity than moving coil units, their frequency response curves are relatively more stable, and their sound is more delicate. The advantages of the moving coil unit are mature technology, lower cost, and the low-frequency sound is more solid and natural than the moving iron unit.

The relationship between sound unit size and sound quality

Many headphone advertisements lead to misunderstandings. One is that the larger the sound unit, the better the sound quality. My personal opinion is that the larger the sound unit, the better the bass will be. But it does not mean that the larger the sound unit, the better the overall sound quality of the headset.

Compared with the size of the sound unit, the type of sound unit has a greater impact on the sound quality of headphones.

What is graphene diaphragm

As the name suggests, the diaphragm uses graphene as the raw material. Graphene is characterized by being hard, light and thin. It is a highly conductive and flexible composite material.

The diaphragm made of graphene can avoid unnecessary vibration due to its rigidity and produce high-reduced sound. In addition, its thinness and lightness can reduce the size and weight of the headphone sound unit, thereby indirectly improving the wearing comfort of the headset.

Some terms describing sound quality

When commenting on a headset or speaker with good sound quality, many people will usually only say that the sound quality is good or good, but it is difficult to say clearly what is good. Of course, I am the same.

The terms used to judge the sound quality of headphones include: sound range, sound quality, timbre, sound coloration, signal-to-noise ratio, distortion, brightness, layering, sound field, low-frequency dive, resolution, etc.

1. Sound range: The range between the highest and lowest frequencies that a sound can achieve.

2. Sound quality: A simple measure of the quality of the sound emitted by the sound emitter, such as whether it has a sense of layering, whether the treble is bright, whether the bass is rich, and whether the distortion is small.

3. Timbre: Determined by the material and structure of the sound-emitting body, it is a word that describes the sensory characteristics of sound. For example, different musical instruments such as violin and pipa can describe the different timbres they produce.

4. Sound coloration: The rendering of sound, which means that the sound signal emitted has more (or less) modifications to the sound.

5. Signal-to-noise ratio: The contrast between the useful components in the sound signal and the noise. The higher the signal-to-noise ratio, the lower the noise generated.

6. Distortion: The output sound signal cannot reproduce the input signal, which means that the sound emitted by the sound emitter does not match the original sound.

7. Brightness: refers to highlighting the high frequencies from 4kHz to 8kHz.

8. Sense of layering: Feel how clearly the sound from the sound emitter is transmitted layer by layer.

9. Sound field: The sound sounds like you are on the scene, and the sound can be expressed in the front, rear, left, and right directions.

10. Low frequency dive: the lowest frequency at which the sound emitter can emit sound.

11. Analytical power: Ability to clearly express subtle changes in sound.

In addition to the words listed above, there are many words that describe the sound quality, which we need to explore slowly.

How to use headphones reasonably

Headphones are a tool for us to listen to sound, whether they are wired headphones, Bluetooth headphones, or noise-canceling headphones with specific functions. Ultimately, it is so that we can enjoy better music. We must be scientific and reasonable when using headphones, and do not affect our hearing due to excessive or unreasonable use.

1. reasonable volume

In order to pursue the shocking feeling brought by the sound, or to use the sound of headphones to cover up the noise outside, some friends do not hesitate to turn the volume to the maximum. This behavior can easily damage hearing. Experts recommend listening to music at 60% of maximum volume or less.

2. Do not wear in-ear headphones for long periods of time

Because in-ear headphones extend into the ear canal, the sound emitted by the headphones is very close to the eardrum. The vibration of the sound from wearing the headphones for a long time can easily damage the eardrum. Of course, there is no problem with normal wearing for three or two hours, and the battery life of the popular in-ear Bluetooth headsets does not allow for too long wearing.

3. Use headphones whenever possible

The sound-generating unit of the headset is at a certain distance from the eardrum, so the energy generated by the sound has less impact on the eardrum. Moreover, headphones do not put a certain amount of pressure on the ear canal like in-ear headphones.

Above, there is still a lot that I can tell you about the knowledge about headphones and their use, and I will continue to output them in the future.