Bluegrass is something that is hard to pin down, but you certainly know it when you hear it. The distinctive sounds of banjo, mandolin, and guitar blend together in a unique way that certainly sounds like bluegrass.
But bluegrass is a broad term for a wide range of music. The genre of bluegrass is comprised of many unique styles of playing music that place equal value on both the roots and traditions of the genre as well as innovation within the genre. There aren’t many genres out there that give this reverence to both tradition and innovation. These seemingly contradictory values are what set bluegrass apart as a genre.
The lines drawn between bluegrass and other styles are getting increasingly blurred. While traditionalists will stick to the guitar, banjo, mandolin, upright bass, and a whole bunch of vocalists, we see a number of bands in the modern days playing around with the definition of bluegrass. Whether they are playing modern style music on traditional bluegrass instruments (e.g. Mumford and Sons), or playing bluegrass style music with a drum set and electric guitars (e.g. The Avert Brothers), bluegrass influences are plainly seen in today’s popular music.
So finally, what is bluegrass exactly? I would say that bluegrass is simply the music of the Appalachians, containing a mix of experiences and influences from the backgrounds of the people living in the Appalachians.