Why the spekaer emit noise?

To analyze the usage, there are a few reasons explain why the speakers emit buzz sound or noise:1. Speaker is a passive component, and the drive circuit decides the sound. Therefore, giving the correct power and waveform to the speaker is the basic request.The too large power will lead to the too big amplitude of the diaphragm. The slight problem is distortion, but the serious problem is that the diaphragm might hit the mechanism or the magnet and cause the buzz sound. The basic waveform to drive the speaker is sine wave, if we give square wave or other waves, the efficiency of the speaker will reduce and easily get heated, the buzz sound may happen as a matter of course.2. The enclosure design of the product will also affect the quality of the sound. The well designed enclosure can improve the frequency response curve of the speaker.The area of sound apertures of the enclosure at least request over 1/8 area of the surface. We need to keep enough vibration space between the case and the diaphragm to avoid the diaphragm hitting the case when it works and emits the noise.

Small speaker with high SPL?

In order to increase sound pressure level, we need to vibrate more air molecule by more power under unit time.For the two sizes speakers, the area of diaphragms of the 15mm speakers are around 176mm square (7.5*7.5*3.14),and the 20mm size speakers are around 314mm square(10*10*3.14). The 20mm speakers are only bigger by5 mm/ 25%, however, the diaphragm are bigger by 78%. Therefore when we input the same power, the 20mmspeakers can vibrate more air at the same time, and it result in higher sound pressure level.Generally, the speaker in bigger size can provide lower frequency response which is better for human’saudition. On the other side, we can also provide the smaller speakers more power to make higher soundpressure level, but it is limited by,1. Acceptability of the diaphragms2. Thermolysis of the speakers3. After increasing the power, frequency response will change too(because thicker diaphragm, heavier coil..etc)Therefore, what we can do is reform the material and the structure of the speakers to increase sound pressure level,but if it is possible to choose the bigger size, the problem of the lower sound pressure level will be improved immediately.