No. Any sound effects (or music) in our library Licensed under the CC0 1.0 Universal License can be used free of attribution for any member (Basic or Gold). These sounds are essentially in the public domain and you can use them as you wish. We only feature a small range of CC0 1.0 Licensed sounds (just a few hundred) and added them to fill some gaps of sounds we don’t yet have. Check the license type for any of our sounds on each sound result. The majority of our sounds are released under our Standard License which does require attribution for Basic members.