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, more fully, a speaker system) is a combination of one or more speaker drivers, an enclosure, and electrical connections (possibly including a crossover network). The speaker driver is an ...

diaphragm Diaphragm may refer to: Anatomy * Thoracic diaphragm, a thin sheet of muscle between the thorax and the abdomen * Pelvic diaphragm or pelvic floor, a pelvic structure * Urogenital diaphragm or triangular ligament, a pelvic structure Other * Diap ...

s. 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. Th ...

) 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 In geometry, a cone is a three-dimensional figure that tapers smoothly from a flat base (typically a circle) to a point not contained in the base, called the '' apex'' or '' vertex''. A cone is formed by a set of line segments, half-lines ...

. 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 from 2,000 to 20,000 Hertz, Hz. The name is derived from the high pitched sound ...

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 {{Sound-tech-stub