Dust caps are used in the daily use of mid-bass speaker units. The main function of the dust cap is to prevent dust particles from falling into the voice coil, affecting the voice coil and causing abnormally poor pronunciation of the speaker unit. In addition, the design of the dust cap also affects the sound effect of the speaker. For example, the material of the speaker’s dust cap is mostly made of paper, cloth, non-woven fabric and metal film, etc., which has a reinforcing effect on the drum paper of the speaker.
And the common concave and convex dust caps in the market, the difference in their appearance design also has a different impact on the performance of the sound quality characteristics of the speakers where they are located.
First of all, the important difference between the concave dust cap and the convex dust cap is the difference in the vibration mode and the degree of resonance it causes, which directly determines the difference between the two in sound characteristics and frequency response curve characteristics. (For reference: Relationship between dust cap shape and high frequency characteristics)
- The convex dust cap can strongly suppress the split vibration of the horn, and can filter out some excess high-frequency signals; at the same time, due to its large resonance degree, the peak value of the curve is high, and the flatness of the frequency response curve is relatively high.
- The concave dust cap has a relatively low degree of resonance and a relatively low peak value of the curve. It can achieve an ideal flatness in the shape of the curve and have a better directivity.
Generally speaking, a speaker with a convex dust cap has a soft and in-ear sound, but the resolution is relatively weak and the sound is thicker; while a speaker with a concave cap, the sound is clear and bright, has a more obvious sound.