As the name suggests, a mandolin banjo is a cross between the two instruments and is a member of the banjo string family with distinct characteristics of a mandolin. It is often confused with a banjolin, which is an entirely different instrument. The instrument has a perfectly round belly made from a drumhead with a neck that is shorter than a banjo's extending from the center out. The sound it produces is similar to the twang of the banjo often heard in bluegrass music, but it is quieter than a banjo and louder than a mandolin. In America, W.A. Cole made the instrument known in 1918 when he perfected the art of playing it.
A mandolin banjo looks just like a banjo at first glance, but it is quite different upon closer examination. The body of the instrument is round like a banjo’s, and the top profile is made from similar materials used on the heads of drums. The backside is made from a light weight wood, and it may be open or constructed with a resonator which is similar to a banjo. Its difference from a banjo lies in the neck of the instrument, which is designed like the neck of a mandolin. The fixed and fretted neck is the same length and has eight strings that are arranged in pairs over four courses like a mandolin.
The mandolin banjo produces a rich, full sound suitable for songs with clearly identifiable melodies. It is not suitable for harder-sounding tunes, such as an Irish jig, because the instrument has as many strings as the mandolin. The mandolin produces a much softer tone than the four-string banjo, and it is tuned in the same manner as a mandolin. The size of the head, or belly, also plays an important role in the amount of sound produced by the instrument. Smaller-sized heads produce softer sounds while larger heads are louder.
The mandolin banjo gained popularity in the 1920s when banjo orchestras became part of mainstream American music. It was created by the mandolin manufacturer W.A. Cole for mandolin players requiring an instrument with more volume than the mandolin. Other manufacturers of string instruments, such as Gibson and Windsor, began the mass production of the mandolin banjo. In recent years, the number of people who play this instrument has fallen drastically. For a brief period between 1970 and 1980, it was used as a replacement for the banjo in studio recordings of popular music.