Copyright in a piece of music is usually first owned by its “author”. The “author” is usually the person who first records the music in some way—for example, writes it down or records it on tape. However, a person who merely writes out music played, sung or recorded by someone else is not an author, if all that that person does is write out the other person’s creation exactly.
Ideas are not protected by copyright, so you are free to create a piece based on someone else’s idea. However, you must be careful to ensure that you do not reproduce a “substantial part”, that is, an important or distinctive part, of the way someone else has expressed their idea.
It can be particularly difficult in the context of music to distinguish between an idea and its expression in a particular work. If your work incorporates elements or melodies of another person’s work, you may need to get permission or specific legal advice.
The creator of a musical work or lyrics is the person who writes the work (that is, the person who composes the melody and harmony of the musical work or the words which make up the lyrics). A person who just gives suggestions or ideas is not a creator, and has no claim to own copyright.
If a person arranges a piece of music you have written, they will generally own the copyright in the arrangement, even though you will retain copyright in your original. However, the arranger will not generally be able to use the arrangement without your permission, because in doing so they will be using your tune. You will usually be able to use the arrangement for the purposes for which you commissioned it.
To avoid complications and disputes arising in this situation, it’s a good idea for you to reach an agreement (preferably in writing) about ownership of copyright before the work is done. You could, for example, require the arranger or transcriber to assign you any copyright in the work he or she creates. Alternatively, that person could license you to use his or her copyright for certain purposes.
Generally, new lyrics to a song are likely to be a new literary work, so the first copyright owner of the new lyrics will generally be the creator or his or her employer. However, if a parody includes a substantial part of an original work, anyone using the parody version will also generally need to consider whether or not they need permission from any of the owners of copyright (including in relation to the parodic version and in the underlying work).
The answer to this type of question will depend on all the facts.
If the writers or co-writers of a song come into rehearsals with a song already completely written, and the additional words are added at that stage, the ex-singer may have a claim to be a co-writer of the lyrics containing those additional words. However, the band could decide to drop the ex-singer’s contribution, and therefore not use the version over which the singer might have a co-writer claim.
However, if a band creates material co-operatively, or if a number of suggestions are incorporated into a song (for example, during rehearsal), it may be that all the contributing band members have a claim to be writers or co-writers of the entire song. In such a case, it may not be possible merely to remove words or change the song a little so as to deny someone a co-writer credit.
In practice, it will often be really hard to work out whether or not a band member who has contributed to a song is a co-writer. This is why it is best for a band to have a clear written agreement which deals with issues such as how copyright will be dealt with and who is entitled to copyright monies generated from material played by the band.