This curious instrument is a Stroh violin, also known as a Strohviol. It was invented by John Mathias Stroh as a violin for use in recording. The acoustical recording process used in the first quarter of the 20th century favored louder instruments that projected well. Brass instruments such as cornets and trombones generally were picked up clearly by recording horns. Flutes and piccolos also recorded easily. Members of the string family did not fare so well during the early days of recording and the Stroh Violin was a solution to this problem.
The Stroh violin incorporated a vibrating diaphragm and amplifying horn, in much in the same way as phonographs and talking machines of the day. While the large horn directed the musical tones towards the recording horn, the smaller horn was positioned by the player's ear and acted as a monitor. Stroh Violins came into regular use in 1904. However, as acoustical recording techniques improved—circa 1910 to 1915—traditional violins replaced them in recording studios.