The dust cap (also known as dust dome, or dome) is a gently curved dome mounted either in concave or convex orientation over the central hole of most

loudspeaker A loudspeaker (commonly referred to as a speaker or speaker driver) is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A ''speaker system'', also often simply referred to as a "speaker" or ...

diaphragms. It protects the inner mechanics (such as the ''pole pieces'' and the

voice coil A voice coil (consisting of a former, collar, and winding) is the coil of wire attached to the apex of a loudspeaker cone. It provides the motive force to the cone by the reaction of a magnetic field to the current passing through it. The term ...

) from small particles (which can cause ''rubs'') and other contamination. Dust caps can also contribute structural integrity to the voice coil assembly or the

cone A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex. A cone is formed by a set of line segments, half-lines, or lines co ...

. In some loudspeaker designs dust caps can also be part of the acoustic design of the driver by radiating high frequency energy or suppressing it. Typically the dust cap is made of the same material as the cone. In some

tweeter A tweeter or treble speaker is a special type of loudspeaker (usually dome, inverse dome or horn-type) that is designed to produce high audio frequencies, typically deliver high frequencies up to 100 kHz. The name is derived from the high ...

designs, the dome is in fact the only sound radiating surface and so it performs both roles.

References

* ALM
NP-002
Dust Cap Styles & Nomenclature * ALM
DG-002
Dimensioning & Tolerancing Guidelines for Dust Caps * ALM
MG-002
Measurement Guidelines for Dust Caps * ALM
TM-213
Test Method for Measurement of Dust Cap Mass * ''Sound Engineering'' from Loctite Loudspeakers