From HyperTexbook :
The frequency range of dog hearing is approximately 40 Hz to 60,000 Hz, of course depending on the breed of dog as well as its age. Like humans, dogs can begin to go deaf as they become older. In some breeds of dogs it is natural for them to go completely deaf in their old age. So, no they can't hear in the 20 hertz range. They can feel it but not hear it.
