If so, how great an impact can such sound healing have on the great array of human problems?

You are seeing intuitively, the nature of energetic disarray as a result of karmic influences might be amenable to sound vibrations in altering something for the better in alleviating symptoms. But we have told you previously, very clearly, and emphatically, that the reach of sound healing is more a surface treatment than a deep answer for the energetic problems brought about by negative karma. It will not change what is going on in other timelines that are the points of origin, and that is the major difficulty here. It can have value, but that will be constrained for long-term issues and problems by the lack of reach and sophistication and delivery, due to lack of knowledge for implementation and optimization.