Hi Roncla It might be usefull for you to know that scientists have been using wave cancellation of light waves for decades now. The dicipline is called Interferometry and can be used for ALL electromagnetic waves--no exception. All of the formulas will apply to sound waves as well as many of the measuring techniques. I have spent the last 25 years in the Laser and acousto-optics field and we use wave interference (cancellation you call it) to make light jump through hoops and sit up and beg. These are simple and useful techniques which could be applied to longer wavelengths such as sound. Best wishes Ron Brady