Acoustics - Large models convergence

Hi,

I'm driving crazy about this subject. I think don't know many things about this model, but regardless how mesh, solver configuration (multigrid, iterative, direct, etc.) or any other thing I change doesn't matters, it can't reach the convergence.

I'm trying to simulate the noise generated by a solid source that emits noise in all frequencies, like a power transformer, in an electrical distribution substation. I'm using the acoustics module in the frequency domain.

I don't know very well how to set the sources pressure (or the pressure level) with the boundary conditions. I'm using the "pressure" boundary condition setting an arbitrary pressure in order to perform a test.

I'm using an iterative solver with multigrid method (2 or 3 levels), with Krylov preconditioning. Then I use SOR or Jacobi methods.

No matter if set or not a parametric sweep (for frequencies), the solver not converge.

There's any "trick" or something that guides me to reach the convergence in these type of models?

Please, see the attached images in order to understand the described above.

Thanks in advance.