Why do you ask?
Two houses ago, I bought a good power conditioner because I thought I had bad power. It did some, but. Then I moved to the country and my system opened up like I had just bought a brand new everything! Now I’m back in the city and in the evenings, my system sounds harsh at louder levels. Sax and some electric guitars just drill into my head! So the other day I ordered a Entech Powerline noise analyzer. I haven’t received it yet, but I am interested to see what it does.