I have an Echo Plus and an Echo Dot. The Plus is in the living room. The Dot is in the bedroom. I stand next to the Plus and say Alexa... the ring pulses and stops, and the Dot in the bedroom starts talking, usually to say "I don't know..."
I am standing RIGHT NEXT TO THE PLUS. I even lower my voice, and the Dot still picks up.
This is just one of the many issues we are having with these devices. Turning on "Johns Light" and then the next time saying "I don't know Johns Light". Tell it to do something, and it just beeps and stops. Rarely does any of this show up in History, so I have no idea what this device thought I said. I did "My Voice" when I set it up.
All of this equipment is about ready to go back to Best Buy.