For a side project away from his band Nickel Creek , Chris Thile knew he wanted to form a five-piece string band that featured mandolin , violin , banjo , acoustic guitar , and double bass . Thile also wanted the band to feature his friend and fiddle player Gabe Witcher , but didnâ t know what kind of band he wanted it to be . For one of his side projects , Chris Thile knew he wanted to form a string quintet composed of mandolin , violin , banjo , guitar , and bass with childhood friend and fiddler Gabe Witcher , but didnâ t know which direction he wanted to take the band .