Bell Mode

A type of vibration or resonance that is found in the cross section of a cylinder and that is similar to the fundamental mode of a bell. In speakers, bell modes can occur as resonances around the outside of the speaker cone that are related to the radius and circumference of the cone. Curvalinear, or trumpet, cones are largely immune to bell modes, and other speakers use corrugations in parts of the cone to reduce or prevent these resonances.