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