Old-time music is a genre of North American folk music. It developed along with various North American folk dances, such as square dancing, contra dancing and buck dancing. It is played on acoustic instruments, generally centering on a combination of fiddle and plucked string instruments, most often the 5-string banjo without a resonator pan, guitar, and mandolin. Together, they form an ensemble called the string band, which along with the simple banjo–fiddle duet have historically been the most common configurations to play old-time music. The genre is considered by some to be a precursor to modern country music, but it also has a contemporary active subculture of musicians in various parts of the United States. Old-time music can generally be distinguished from the more widely known bluegrass genre by the use of cross-tunings on the fiddle, by all melody instruments playing in unison, by a lack of individual instruments taking breaks to improvise, by sessions remaining in one tuning or key for an extended period, and by banjos being frailed instead of finger-picked and lacking resonators, giving them a softer, mellower sound. In contrast, bluegrass banjos usually have a resonator pan attached and are typically played 3-finger-style with steel finger picks.