This article introduces a small part of the relevant Speaker calculation knowledge, I hope to help everyone. Inverter calculation: Take the cross-sectional area of ​​the inverter tube S = 0.1 ~ 0.4 times the effective vibration area of ​​the woofer. The larger the area, the higher the low-frequency radiation efficiency, but the longer the tube length; the length of the inverter tube L = c × c × S / (4 × pi × pi × f × f × V)-0.82 root number S (units are calculated in centimeters) where c = 34400cm / s (speed of sound), f is the resonant frequency of the woofer, V is about the effective volume of the cabinet 40mm outer diameter The larger the volume of the cabinet, the deeper the low frequency dive, and the Q value will drop accordingly; but after the low frequency, there will be weakness, and you should throw sandbags into the speaker The smaller the volume of the cabinet, the better the low frequency strength, and the Q value will rise, but the resonance frequency of the relative speaker will rise. At this time, you can add more sponges to expand the inner product; The longer the inverter tube, the better the transient characteristics of the speaker, and the deeper the low-frequency dive (but the sense of volume will become smaller). However, if the sound is too long, the sound will be tailed, resulting in worse transient characteristics. If the length is too close to the inner surface of the cabinet, there will be airflow sound, which is not necessary; The shorter the inverter tube, the worse the transient characteristics and the resonant frequency will rise (but the sense of quantity will increase). Related principles: Helmholtz (H · von · Haimuhuozi) is a great 19th-century physicist and physiologist in Germany. The “Conservation of Energyâ€, the head of the three basic conservation laws of mechanics at our university, is his greatest Scientific achievements. The Helmholtz resonance principle is one of Helmholtz's famous achievements in the field of acoustics. First, create a closed cavity composed of an ideal rigid body. This cavity is called a Helmholtz resonance cavity. A hole with a small area relative to the surface area of ​​the cavity is opened on the surface of the cavity. The structure of the hollow rigid body pipe is called "Helmholtz resonator". For a Helmholtz resonator, when the internal air is forcedly compressed by external fluctuations (whether the forced force is applied to the air in the cavity or the air in the pipe, whether the applied external force comes from sound waves or cavity vibration) , The air in the pipe will vibrate, and the air in the cavity will produce a restoring force (in other words, the air in the resonance cavity is an "air spring"). In the case where the wavelength of the sound wave is much larger than the geometric scale of the resonator, it can be considered that the kinetic energy of the air vibration in the resonator is concentrated on the movement of the air in the pipe, and the potential energy is only related to the elastic deformation of the air in the cavity. In this way, this resonator is a one-dimensional vibration system composed of the effective mass of air in the pipeline and the elasticity of the air in the cavity, so it has a resonance phenomenon to the applied fluctuations, and its natural frequency is: (see figure). In the formula, f0 is the lowest resonance frequency of Helmholtz resonator, c is the speed of sound, S is the cross-sectional area of ​​the pipe, d is the diameter of the pipe, l is the length of the pipe, and V is the volume of the cavity. Under the action of a certain intensity of vibration, at this frequency, the vibration speed of the air in the pipeline reaches the maximum. This is the so-called "Helmholtz resonance principle". Smd Mic,Smd Microphone,Smd Condenser Microphone,Smd Dynamic Microphone NINGBO SANCO ELECTRONICS CO., LTD. , https://www.sancobuzzer.com
The simple debugging of the inverted speaker: (I have summarized it after reading, but I have not practiced it) 