Mandolin-banjo became more popular. In the heyday of mandolin orchestras and banjo bands (late 19th–early 20th century), all sorts of instruments were produced. The mandolin-banjo is one of the hybrids that resulted. It enabled mandolinists to produce a banjo sound without having to learn that instrument's fingerings. The instrument adds the banjo's volume to the mandolin. The banjolin is different from the banjo-mandolin in the number of strings that it has. Banjolins today are supposed to have four strings instead of 8 strings (in courses or pairs). However, that distinction is not universal; the "banjolin" name was patented in 1885 by
Octave mandolin also varies widely, from as few as 17 to as many as 24 frets: 18 or 19 frets is typical. From the mid-20th century on, a number of makers have produced octave mandolins with guitar-shaped (e.g., the "hourglass" or "figure-8") bodies. These instruments are typically constructed essentially like acoustic guitars, with similar woods and internal bracing. the neck, however, is much narrower, and supports the mandolin string layout, rather than the traditional 6-strings of the guitar. As with the mandolin and mandola, the octave mandolin has four courses of two strings each. The two strings in each course are tuned