In terms of headphones, most of them generally talk about the purchase of headphones, the classification of headphones, etc. today we don't talk about these. The development of science and technology is always in the direction of high precision. Let's talk about something deeper, the diaphragm of dynamic loudspeaker unit.
Moving coil loudspeaker unit is a very mature loudspeaker structure design. In addition to being applied to earphone products, most loudspeaker units adopt similar design. The moving coil unit is a magnetic field generated by the current passing through the "coil", and this magnetic field produces a force effect with the magnetic field of the magnet located on the horn support, and the coil will move; The horn diaphragm is connected to the "coil" and moves with it to vibrate the air, realizing the process from electricity to sound.
In the general horn unit, the design requirements of the diaphragm are that the lighter the mass and the better the rigidity. Such diaphragm can completely convert the kinetic energy of the coil into sound. This is because in the design of the horn unit, there are soft edge parts of the diaphragm and positioning diaphragm for balancing the movement of the diaphragm, but such parts are "cancelled" in the headphone horn.
The main reason for this "cancellation" is because of the volume. Therefore, the diaphragm design of earphone horn is very important, because it not only needs enough rigidity, but also must maintain a certain softness to meet the movement of the coil. Therefore, the design of diaphragm has been optimized and strengthened. As can be seen from the above figure, the outer ring of the diaphragm of the unit is designed with reverse embossing, which not only strengthens the rigidity of the diaphragm, but also ensures the high-frequency performance of the horn unit.
However, with the progress and development of the acoustic industry, the diaphragm has also changed, and new diaphragm technologies have begun to appear. Here are some common ones.
A bacterium called asetbactar produces very fine cellulose after eating sugars. Using the most advanced biotechnology, it took about 2 days to culture the biological fiber to a thickness of 2mm. Then, dehydrate it, and then compress it to 20 with the metal abrasive tool for making the diaphragm μ M thickness. Thus, the biological diaphragm was born. This diaphragm has the speed of sound (square root of rigidity / density) comparable to that of aluminum film and titanium film, and has the unique slender of paper, so it can reproduce extremely natural sound. The timbre of biofilm earphones is characterized by high frequency but not sharp, which gives people a very broad feeling, and the resolution of details is very high.
As the name suggests, the diaphragm of the plane diaphragm is flat, which is different from the spiral curve design of other diaphragms. It is like a piece of white paper. The plane diaphragm is generally used on electrostatic earphones, and now it is also used on dynamic earphones. The plane diaphragm brings higher sound definition. A simple analogy, if other diaphragms are equivalent to HD TV, The plane diaphragm is equivalent to ultra high definition (4K) TV. Its representative works are hifiman HE-6, the leading brand of walkman in China, and foxt50rp in the United States.
A kind of metal diaphragm, in addition to aluminum diaphragm. Beryllium diaphragm, titanium diaphragm is characterized by fast heat conduction, high specific elasticity and good moisture resistance. The disadvantage is that the damping is small, which will increase the peak and valley of the frequency response curve and worsen the transient effect at the back edge. It is suitable for listening to pop music.
Carbon diaphragm is the patent of JVC. Carbon material is recognized by the acoustic industry as the best acoustic diaphragm material at present, and carbon nanotechnology is one of the core technologies of JVC. This material has been verified to have some very excellent characteristics. On the acoustic response curve, it is obviously superior to the simple coating diaphragm technology such as aluminum diaphragm and titanium diaphragm, and also superior to the multi-layer diaphragm technology. It can be said that the carbon diaphragm is the core breakthrough technology made by JVC since the wood diaphragm. It is characterized by sufficient rigidity at intermediate frequency and good elasticity at low frequency.
Wood diaphragm is also the technical core of JVC. JVC is worthy of being a wonderful flower in the industry. The raw material of wood diaphragm is New Zealand birch log, which is sliced into 80 thick pieces μ M, and then it is made by softening - Stamping - repeated fixing and forming. The original characteristics of wood such as easy cracking, deformation and insufficient toughness are avoided, and the service life is improved. The representative work is fx800 of JVC. Due to the wooden diaphragm adopted by fx800, fx800 not only has the best bass transient response in the world, but also realizes the details and expressiveness of bass. In order to achieve perfect acoustic response, JVC first adopted wooden cavity in the cavity to ensure the consistency of overall acoustic response, ensure the beauty of unity and balance, and realize the sound effect of "double wood combination, perfect and invincible".
Liquid crystal diaphragm
That is, liquid crystal polymer diaphragm, which is Sony's technology. According to Sony's official statement, the liquid crystal polymer diaphragm is hard and sensitive, which can provide the hardness and internal loss required to restore balanced and highly accurate medium and high frequency sound quality, so as to achieve high-definition midrange and treble effects. The manufacturing principle is very simple, that is, the liquid crystal polymer material is pressed in the mold. How to do it is a secret. If I can, I won't be here.
The above are several common diaphragm technologies and representative works. Of course, there are far more kinds of diaphragm. In order to find a good sound, people continue to try new materials and technologies, as well as graphite diaphragm, polypropylene diaphragm, magnesium silicate polymer diaphragm, aramid woven diaphragm, etc. These diaphragm are not very common, there are few representative works, and it is difficult to buy, I won't give a detailed introduction for the time being. I would like to emphasize that the development of diaphragm technology is a continuous progress process for acoustics, but our requirements for headphones should not blindly pursue new and strange ones. We should choose a pair of headphones suitable for ourselves, not based on parameters or technology, but to listen and like the sound produced by this pair of headphones, Blind pursuit is a costly and meaningless behavior.