How to revert Audio button to old Speaker Phone default?

I do not want to be asked to choose an audio option every time I make a call and just want to switch to speaker phone, as I usually do, and used to do, easily. I have turned off Bluetooth from my phone's settings and it still asks me if I want to connect with my iMacBook Pro or my Mac Mini. I can't turn the bluetooth off on the mini because I need it on for my wireless mouse and keyboard. Can I change the Audio button back to the old Speaker Phone default?