Thank you Retired plbr for your advice and to this forum for solving the problem. I turned off the water to the stool that is near tub for 24 hours. No more noises.
I then let a bit of water leak past the flapper valve by lifting the chain slightly. Suddently the float valve started making the noise that I referred to.
I checked the flapper value and found that it was eroding and probably had become permiable because it wasn’t visibly leaking into the bowl. I replaced it and tickered with the adjustment screws on the float value and was able to stop the noise.
Thank you very much. I would never have guessed that something this small could make such a loud noise throughout the house. The bathtub has fiberglass enclosures that act like an amplifier.