Bass horn. This instrument, formerly much used in bands, has declined much since the introduction of the Ophicleide, which instrument it somewhat resembles. The player of the bass horn should possess a quick and correct ear, and a knowledge of thorough bass, in order to perform upon that instrument acceptably. The instrument has been found rather imperfect, and is not now much used. There is a French horn called bass horn, and the directions for learning that instrument will be found under the term French Horn.