In the more than 100 years of development history of horn loudspeaker, material selection, craftsmanship, and structural forms have always been changing. Different materials and qualities have created different sound characteristics, and they also have their own advantages and disadvantages.
At present, the popular speaker diaphragm materials on the market are paper cone, plastic, metal and synthetic fiber.
Paper cone diaphragm
The paper cone diaphragm appeared the earliest, and it is also the most common horn speaker diaphragm material. At present, it has a very mature technical level. The production process is roughly as follows. The pulp is poured into the designed mold, dried and then subjected to a series of subsequent processing. The specific material composition, proportion and processing method are different for each brand and belong to their trade secrets.
The sound characteristics of this type of diaphragm are smooth and natural, with few distinctive stimulation parts, which are in line with most people's tastes. Due to the interweaving of the internal fibers, the paper cone diaphragm can quickly absorb the sound energy during the transmission process, so the damping characteristics are ideal. In addition, the paper cone also has the advantages of light weight and high energy conversion efficiency. The disadvantage is that the paper cone is more sensitive to temperature and humidity, and is obviously affected by the environment. After several extreme environmental changes, it may produce irreversible deformation. However, with the advancement of technology, the waterproof performance of paper cones will get better and better.
Plastic diaphragm
Also known as PP sound cone, it is generally made of polypropylene material, which is also a common diaphragm material. Its moisture-proof and waterproof effect is much better than that of the paper cone diaphragm, but it will also be slightly affected. The PP sound cone also has excellent damping characteristics, and the hearing is soft and natural, but the rigidity is relatively general, and the high frequency performance is prone to distortion.
Because it is a chorus material, the PP sound cone is easy to improve later. For example, on the existing basis, it can be achieved by adding other materials to overcome certain deficiencies to achieve an ideal state.
Metal diaphragm
The metal diaphragm is generally made of aluminum or its alloy material, which has distinct characteristics in terms of sound, outstanding performance in terms of dynamics and analysis, and can control distortion well. It's just that the damping characteristics of the metal diaphragm are relatively weak, and it is easy to produce "metallic sound" at high frequencies (that is, the phenomenon of basin splitting generated at the high frequency end), but it can be improved by applying special paint on the surface of the diaphragm.
In addition, the metal diaphragm has more design requirements on the circuit, which will inevitably increase the cost.
Synthetic fiber diaphragm
The material of the synthetic fiber diaphragm is transplanted from aviation and military materials. It is light in weight, has high strength and rigidity, and has the characteristics of various other material diaphragms, that is, the manufacturing cost is high, which is generally found in high-end speakers.
The damping characteristics of the synthetic fiber diaphragm still need to be strengthened, which can be achieved by the current methods such as sandwich or coating.
In addition to the above four types of diaphragms, there are also horn diaphragms made of graphite fiber, glass fiber, carbon fiber, bakelite, etc., but they are not widely used and are rarely seen in the market.
In fact, the sound characteristics of different speakers have different requirements for the diaphragm material, and the diaphragm materials of the tweeter and the woofer are different.
The tweeter is divided into three categories: hard dome, soft dome and composite membrane dome.
The materials for making the bass unit are mainly paper cones, ceramic basins, bulletproof cloth, wool basins, polypropylene and so on.
