If ya' grow up in Virgina - as I did - you know the difference between "old time music", "bluegrass music" and "mountain music"... The "old time" and "mountain music" are closer related than "bluegrass music"... All three use the same instrumentation so it's more about the lyrics and the rhythm... "Blue grass" has one rhythm: balls to the wall fast...

"Old time" and "mountain music" have a different rhythm... Slower sometimes... Pauses... "Old time" and "mountain" also are more apt to have Biblical or spirituality references...

Kinda hard to explain if ya' ain't been around it all...

B~