A phonofiddle is a class of stringed musical instruments that are played with a bow and use a phonograph type reproducer as a voice-box.
The sound producing diaphragm may be a metal cone as in the Stroh violin or a mica sheet as in the instruments made by A. T. Howson, London and the Stroviols company of Britain. The sound generated by the vibrations from the string or strings are transferred through the bridge to a connecting arm into the center of the diaphragm within the reproducer. The vibrating column of air is then directed into one or several horns. Johannes Matthias Augustus Stroh patented the use of a metal diaphragm in the voice-box (reproducer) of a violin in 1899. The use of phonograph reproducer with mica Isinglass diaphragms allowed the cost of production to be reduced. Phonofiddles had a brief period of popularity as studio instruments for acoustic recording of phonograph records as the energy of the sound could be directed into the collection horn of the recording equipment. Later the phonofiddle was relegated to novelty performances such as those of The Temperance Seven and Bennett & Williams.