Any one measured the EMI/RFI attenuation performance of audiophile power conditioners?

You can do swaps/blind ab in my room (with my streamer+DAC+amp) between my Audioquest Niagara and wall. I have in the past and will point out over and over, 30/30 times (to statistical significance). It is that freaking obvious to my ears!

These type of recurring threads are tired and ignorant.

I know, it's like talking about the weather.  I have the Niagara 5000.  It is also an obvious improvement for me.  Expensive and not as much fun as buying an amp, DAC or speakers but the improvement in sound is unmistakable for me.

@audio_phool 

I’m not well versed in power line noise and the resulting issues with a systems sound quality, but I thought that noise at 1Mhz was preferred to noise within the auditory frequencies and that such noise could be easily filtered.  Power conditioners and systems of conditioning like with Shunyata, or Audioquest claim to also limit noise generated by component such as switching power supplies.  So, I’m not clear on why filtering of 1 MHz signals is a key point of your post.

Audio consumers have complained for decades that power conditioner manufacturers don’t publish object measure of their products direct impact upon what we hear through our electronics.  Has anyone quantified what attributes must be measured and how they are measured?  I purchased the Everest and associated power cables on a ninety day trial and didn’t return it because it was the single greatest improvement that I had heard in my system to that point.  I recognize that this is subjective, but what group of measurements can be used to predict the listener’s subjective experience?

@tonywinga I don't understand whats in the performance data which needs to be kept secret even though the method of achieving the performance can be proprietary and hence method can be kept secret. In fact performance numbers are a thing to boast & if I was the mrketing head i will use them everywhere to market the product unless they are terrible & hence need to be kept secret.

Your example of Automotive industry exactly confirms the point which i said, except for the Audiophile industry, every other industry has standard norms and specs to be met, else the product is useless. In audio while sound is highly subjective and hence cannot be standardised the way it's done for other things, power conditioning or EMI reduction is something very well established & measurable thing, yet audiophile grade manufacturers of these products choose to ignore the specification and/or performance data.

@deep_333 I never said any of these products don't make the improvement/changes to the sound. My post was regarding lack of objective measurements/performance data for something which is completely objective. Will FDA accept a new drug if tomorrow the manufactrer will just say I saw improvement in a patient's condition?

Audio_phool

@vonhelmholtz I think you mis-read/interpreted my post. I was not highlighting the importance of noise reduction at 1Mhz, it was highlighted by Shunyata in response to my query about the performance data. They claimed that their Everest & Denali to have 68dB noise suppression at 1 MHz which is best in the field. But then I cited the example of $60 worth of filter from Schaffner to have Noise reduction of 70dB in common mode and 80dB in differential mode at 1MHz.
 

I am of the opinion that impact of power conditioning on SQ is dependent on various factors such as equipment, state of power, person's hearing etc. & hence can not be easily measured. But the performance of a power conditioner in terms of noise reduction is completely objective and measurable.

Audio_phool