Is it forbidden to listen to mouth music (vocal percussion) that contains no musical instruments, such as the songs of Michael Tompkins and Alaa Wardi?

The fatwa is that natural vocal sounds made by a singer, such as "aahs" and chants, do not take the ruling of forbidden musical instruments, even if they resemble the sounds of musical instruments. However, if these sounds are manipulated using musical instruments or computer programs to imitate the sounds of musical instruments, then they are considered music, and listening to them is prohibited.