What is float-free arrangement?

What is the difference between a cover song and an arrangement?

• I can get a licence for a cover song quite easily but in the UK an ‘arrangement’ requires approval from the publishing company and they may have to defer to the artist or their management for approval. I’m not sure how far I can go in adapting a song to my own sound before it becomes an arrangement. Is it a change of instruments? Is it a change in tempo? At the one end I can understand a cover being a faithful reproduction of the song created without using the songwriters actual recording. I also understand that if say, an arranger sits down and creates an arrangement for strings, orchestra etc then a new arrangement has been created that the songwriter or publisher has to approve. I also understand that there is a historical dimension form the days of sheet music and before the recorded version dominated our perception of a song. So, when I create a cover it is accepted that the singers voice is not the same, that the key may be different… but if I replace a guitar with a synthesiser or reduce the length of the song is it still a cover? When is a cover not a cover?

• Answer:

  Historically in music, an 'arrangement' is when you change the orchestration, which is to say you change what instrument is playing what.