Sansui made a light display "watt" meter. I had one in the 70s hooked to my AU 717.
What is the name of the tool?
Forgive my absence of knowledge, but what is the name of the tool that one uses to measure the wattage coming out of ones speakers. I called it a watt meter to my family and got something that measures the watts and current coming from the outlet to the powered device I was using instead, for Christmas.