I'm a bit skeptical about the Entech meters, and what they are actually measuring. I have heard it said that they look in the band 300kHz to 700kHz, so the am medium wave radio band. Whether that is representative of problems in audio is debatable. After all audio gear cheerfully picks up 800+ MHz from mobile phones,
Monster Cable had a variant of the Entech meter that they provided to their cable and conditioner outlets so that a sales person could demonstrate how good the product was. Same as Shunyata do now.
I'm trying to buy one just out of curiousity. If I snag one for not much, I'll do some tests (oh and probably take the back off to find out what is in there...).