The second decline was not as complete as the first. Thousands of people had learned to play the instrument. Even as the second wave of mandolin popularity declined in the <answer>early 20th century,</answer> new versions of the mandolin began to be used in new forms of music. Luthiers created the resonator mandolin, the flatback mandolin, the carved-top or arched-top mandolin, the mandolin-banjo and the electric mandolin. Musicians began playing it in Celtic, Bluegrass, Jazz and Rock-n-Roll styles — and Classical too.
When was the second decline of mandolin popularity?
early 20th century,