Measuring line noise and power conditioners

The audience here simply doesn't know much about noise, including the people fronting noise reduction technology. The subject is codified in many ways by many international organizations. It is based on a knowledge of mathematics and of many other areas of engineering. Because we are supposed to be an organization of music lovers, add our group to the subject of "noise." It isn't nearly as codified and regulated, but still covers a wide area of human reaction to sound.
I am not going to say anything other than that "stupid is as stupid does." If you would like to really understand noise, it's measurement and appreciation, start with yourself. As a human being, interested in music... learn to appreciate the music, not the noise. The best filter I know is your mind. "If you don't mind, it doesn't matter."

While I don't agree with caycol in totality, a good portion of what he is stating is true at least for audio. In a well designed product, high frequency external RF noise is much easier to get rid of than low frequency noise, i.e. in the audio band on power lines, and guess what, low inductance, low capacitance AC cords are not going to help the situation, though consistency of the chassis ground reference between equipment can be critical for low noise.

High frequency RF as measured by these EMI toys does not represent well the much harder to filter frequencies on the AC line that are either in the audio band and/or close it and can sub-modulate down into the audio band.

Where the problems come in is with low level, high impedance signals such as interconnects, whose signal path may include the chassis ground due to intentional (or unintentional) capacitance between the signal ground and chassis ground (usually intentional).

piaudiol, most of the papers you linked have nothing to do with the topic specifically, which really doesn't address the effectiveness of line conditioners either where it matters, nor do they really refute caykol, though they do introduce topics such as ground loops, and hum, that my have nothing to do with EMI filtering at all.

robberrttddidd
High frequency RF as measured by these EMI toys does not represent well the much harder to filter frequencies on the AC line that are either in the audio band and/or close it and can sub-modulate down into the audio band.

>>>>Sub-modulate down to the audio band? Are you high? Radio Waves are not even in the same domain as acoustic waves. How can MHz or GHz electromagnetic waves submodulate down to the acoustic band? It almost sounds like you actually think the acoustic waveform is traveling through the wires and cables.

Wow, I have seen that much jibber jabber since the last time I squeezed your head. You don’t get audio frequencies until the speaker diaphragm moves. Then you get audio, Mr. Smarty Pants. 👖Up until the signal gets to the speaker there is no audio, only current and voltage.