Several methods and systems to generate a playlist based on a frequency ratio are disclosed. In one aspect a method includes, presenting a list of a seed data to a user of a music device, selecting a portion of the seed data based on a preference of a user, and determining an identity of a primary song based on a match between the primary song and the preference of the user. The method also includes providing the user streaming access to the primary song in a database and determining a secondary song based on the primary song. A correlation between the secondary song and the primary song is determined based on an algorithm and the user is provided streaming access to the secondary song. A frequency ratio of the primary song and the secondary song is automatically adjusted in responsive to a selection through a selection tool.