The colludium (col-lew-dee-um) is a harmonic 6-string guitar that has a bridge in the middle that separates the strings into 2 sides. One side is played like a lap or pedal steel (as there are no physical frets) and the other side vibrates at specific harmonic intervals that excite the strings in a sympathetic vibration. Each side has separate pick ups, output channels, volume and tone controls. This allows the player to accentuate, amplify and process harmonic intervals of the original base string tunings.