When using sounds that have already been created you should consider the Legal issues which are split into three categories which are copyright ancillary rights and royalties.
What is Copyright?
Copyright is a form of legal protection given to many kinds of created works such as musical compositions or songs, lyrics, records (CDs,) , books, TV shows and movies. For a work to be protected under copyright, its must be “original” which means that it was not copied from another source; that a person can perceive it and reproduce it; and should have a minimum amount of creativity.
For a musician, copyrights will provide protection for both songs (melody and lyrics) and recordings (CDs, mp3s, etc.). . A song may be fixed by writing it down, recording it (even on a handheld recorder), or saving it to a hard drive on a computer. Playing a song live does not meet the fixed requirement. But, if you record the live erformance, you have now fixed the song.
Once an original piece of work is fixed, the creator has copyright protection automatically.
Ancillary rights would be if you are either the artist, writer, or the creator of the copyrighted music/sound, you own what the law refers to as a bundle of rights that comprise the property, from primary to secondary or subsidiary rights.
Ancillary Rights Enable the screenwriter to receive a percentage of the profits generated by the film in areas such as posters, action figures, books, records, T-shirts, etc. There are ways for music labels to obtain all rights not just in the master recordings but also in the ancillary rights they do this by using the 360 deal, which is a COD (Copyright Ownership Deal) so what the artist would usually keep as invaluable such as profits made from touring those rights would be handled by the label itself.
A royalty is a percentage of gross or net profit to which the creator of a piece of work is entitled which is agreed upon in a contract between the creator and the manufacturer, publisher, agent and/or distributor,Inventors, authors, movie makers, scriptwriters, music composers, musicians and other creators contract with manufacturers, publishers, movie production companies, producers, and distributors to be paid royalties in exchange for a license to manufacture and/or sell the product.