Harmonic Guitars & Electric Tromba-marina

It is extremely hard to classify these 'third bridge' guitars, be they 'harmonic' or 'noise'. The left two are pretty much based on Branca's specification, a third has moveable 3rd bridges (from my own original design from the late seventies) and the rightmost is an 'electro-drone', or most likely an electric 'tromba-marina'.

-- Buzzy