Fibrephones were developed first in 1984 with original Echo City member David Sawyer. They rely on a pretensioned conical fibreglass resonator, which can be used to amplify the sound of various sound sources acoustically.

Echo City has built them to work with bars strings and rotating beater mechanisms. The bar version is the one most commonly used for commissioned installations and it is pictured here in different settings. It uses the standard Echo City beater, with which the player strikes the steel or aluminium bars.