The other night, I saw a tiny bit of a terrible-looking film called Bloodhounds of Broadway. Madonna was singing in a 1920s bar. In the background was a violinist playing a violin with big metal horns poking out of the side. A bit of Googling reveals it was a Stroh Violin, invented in 1899 by Carl Augustus Stroh. It was developed for the early recording industry. Until around 1920, records were cut by the band standing around a large horn connected to a needle scraping the grooves into the master, and strings were hard to record. So Stroh removed the violin's sound chamber and replaced it with a brass (later aluminium) horn attached to the bridge. Later models also had a secondary horn, pointed at the player - probably the first monitor speaker in history. The Stroh should have died out completely in the '20s, but according to this page, they became popular in a small region of Transylvania called Bihor. Perhaps inevitably, Tom Waits uses a Stroh, as do The Kryonics. You can buy a new, Thai made Stroh for $408 from strohviolin.com (or $315 from their eBay shop).They offer this [mp3] unpromising sound sample to prospective buyers. More pictures at Elderly Instruments.