Some prerequisities need to be in place before you can assign an Acoustic Excitation.

  1. Create a Harmonic Acoustics analysis
  2. Add Air to Engineering Data and make sure it has Speed of Sound and Density physical properties
  3. Assign Air to the Solid Body representing the room
  4. Assign an Acoustic Region to All Bodies
  5. Mesh the Solid Body

Now you should be able to assign a Mass Source.

Some of that is automated if you use Ansys 2023 instead of 19.2 with the ACT.