In fact, anything can make a sound when it vibrates. For example, if you vibrate a piece of paper, you can also make a sound, the same.
　　In theory, anything can be made into a diaphragm, but different materials have different values of Young's modulus, Poisson's ratio, density and internal loss, so the sound is different.
　　You mean the paper shell is a diaphragm, but it may be part of it.
　　Because the diaphragm is composed of three parts, it may be one material or three different materials.
　　It is mainly the overhanging edge, the middle bass area and the middle treble area.
　　Because different areas have different effects on different frequencies of sound, good speakers will be made of different materials and processing methods.
　　The function of overhanging edge is mainly vibration, so it is related to the elasticity of the diaphragm and the low-frequency vibration frequency (F0). The middle and low-frequency area is the main area, which is related to the sound size and quality of the loudspeaker. The sound of different materials will be different. For example, the sound of paper will be lower and thicker, and the sound of PET plastic will be sharper, just like the sound of knocking a piece of wood is different from that of knocking a piece of iron The reason is the same, because the speed of sound transmission inside is not the same; and the treble area is mainly the treble of the tube, good tweeters are made of metal ball top, mainly because the high frequency speed needs fast response and transmission.
　　That's the diaphragm.
　　And this kind of electric horn is connected to the voice coil (coil) under the diaphragm by alternating current, so that its changing electric field produces a changing magnetic field, and then cuts the magnetic induction line in the magnetic circuit which has been changed by Huasi and u cup, resulting in movement and sound.
　　It is a process of energy transformation from electric energy to magnetic energy, then from magnetic energy to force, and then from force vibration to sound.
　　In fact, only 2% of the initial energy is converted to sound energy, because the other 98% is converted to heat energy and the energy loss of joint glue.
　　I hope you like electroacoustics.