Or the Halldorophone as it was named by its inventor Halldor Ulfarsson. The banjo was made in Berlin during a workshop for building Halldorophones. These electro-acoustic string instruments which send the sound from their pickups back into their bodies. When the sound has traveled full-circle, it vibrates the strings again and creates an infinite sustain that the player can affect in different ways. For achieving ths an amplifier, a loudspeaker and a guitar pickup are beinig used. During the workshop in Berlin only the acoustic body was constructed from a tambourine and a cake tip. The electronic was made back in Sofia with the help of Svilen Ivanov. Albena is otherwise responsible for the design and the constructuion.