The diaphragm of the speaker affects the sound a lot; let us discuss the affection in the thickness, surface pattern and material.

1. Thickness
The speaker with higher input power, needs thicker diaphragm to match, because the higher input power means the higher load and the stronger vibration will be generated. If the diaphragm is not strong enough, the noise will happen, and even the diaphragm will be ripped by the strong power. With the same diameter, the thicker diaphragm has worse frequency response (FO) at the low frequency (LF); therefore the speaker with higher input power will have higher FO.

2. Pattern
There are two mainly patterns of Mylar diaphragm: concentric circles and radiate patterns (picture. 1 and picture. 2). The different surface patterns will generate different characteristics of FO. For example, picture 3 and picture 4 show the curves of concentric circles and radiate. The concentric circles speaker has higher output S.P.L. before 5 KHz, but dramatically falsl after 5 KHz; the radiate speaker has more stable output S.P.L., but to compare with concentric circles speaker, the output S.P.L. will be lower before 5 KHz. Therefore, depend on the application, we can choose the suitable patterns of diaphragm, the concentric circles is good for the human voice, and the radiate pattern should be selected for playing the music.

3. Material
Mylar, paper and clothes are the main material of diaphragm for mini/ micro speakers, the cost increases in order.

Mylar has the advantages of lower cost and easier to shape up, but mylar is not suitable for the high power or large size speaker; the paper diaphragm also have lower cost but more natural sound than Mylar, however if the diameter is smaller than 30mm, it might cause difficulty to manufacture and the defective rate may increase. Clothes diaphragm, which can change the frequency response by adding different kinds of fibers, has the best sound quality. However, clothes diaphragm is usually used in the large size speakers because of the high cost.