Known in the US as an alto horn, in German as an althorn, and in the UK as tenor horn, this instrument is an aerophone (i.e., a brass wind instrument sounded by buzzing the lips) in Eb, with a conical bore (gradually widening), normally using a bell-shaped mouthpiece. It is most commonly used in marching bands and brass groups, where French horn takes the corresponding parts in symphonic groupings. It has a mellow sound, blends well, and serves as the voice between trombone (or baritone horn, in Bb below) and trumpet or cornet (in Bb above). Its lowest note is concert A below C below middle C, and its highest is Eb above C above middle C. It was invented in the mid-1800s by Adolphe Sax, a Frenchman who is best remembered for inventing the saxophone, as a middle voice in the group known as "saxhorns." It has been made in various forms: most common is a sort of mini-tuba shape, with the bell pointing upward, which helps the voice blend before reaching the audience; the solo horn often looks like an enlarged trumpet, with the bell pointing forward, projecting more toward the audience; another variant has the bell facing backward (for military marching bands that preceded the soldiers, thus helping them hear better and keep better time in marching).