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


I was looking for a very good/robust power conditioner which will clean up reliably very noisy/dirty power supply that I have in my aprtment. While looking for one I went through catlogs of AudioQuest, Shunyata Research, Synergestic Research etc. but no one published charts showing attenuation performance over frequency range like you get for EMI filters from Schurter or Schaffner etc. which are in the industry for EMI/EMC compliance.

Since audio is very subjective, but contrary to audio reproduction Power and EMI/RFI reduction is completely objective and can be clearly demonstrated via attenuation charts.

Hence I am asking if anyone has measured the actual performance of these audiophile power conditioners. I am not denying someone saying they hear improvement after using XYZ product, but since I am talking about power conditioning or EMI reduction it's as objective as it can be.

I am not at all surprised to see all the manufacturers not publishing the performance data, else it would be used in other industries and research fields where it's far more critical and have far more stringent requirements on the performance of conditioner/EMI filters. But I am shocked to see even products ranging above 5-10K are following the same practice of not publishing the results.

Please note I am not a measurement fanatic, but I know where I can chase the measurements and where I can rely on my hearing to gauge the difference.




@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.


@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?

Years ago, a group of engineers in a large manufacturing/test facility (defense/aerospace) were in deep sht with a certain kind of issue. The control system on some sensitive test equipment, one of a kind, one sole manufacturer in the world to meet specs, would freeze up due to some power anomalies that would occur in the midst of weeks long continual tests. Months of power monitoring with the most sensitive/most expensive equipment (that audio guys may have never even heard of) revealed that the monitoring equipment may not have been sensitive enough to catch weird sub-cycle spikes, etc or the ability to capture/characterize such anomalies in that industrial environment. There is nothing else to buy.

Solution: We isolated the control system on that equipment with some very expensive custom iso. transformers. The problem never re-occurred again.

If someone came back and asked me, "where oh where is the measurement/data trail that drove you to your grand solution?" All i could say is, "foff and don’t waste my time, the solution is in place!"...and that’s how it may work in certain types of industries at times.

FDA? Try and figure out all the complexities of the most sophisticated gadget in existence, i.e., the human body first..After that, we can talk about FDA and other crap (Most of your medication is apparently fixing one thing, breaking something else anyways).

Get a couple of engineering degrees, work in field for a few decades, start to get a feel for the limitations of what we can/can’t measure, how much we don’t freaking know in the grand scheme of things, etc, before you get really absolutist with some audio stuff. The internet read low info guys from the likes of ASR are the ones who feel mighty proud of themselves on a daily basis. They know everything there is to know apparently!

Another thought is that in order to publish performance data and avoid litigation, manufacturers must maintain a test lab’s certification and calibration and possibly have their test results certified by an independent laboratory.  That is not cheap.  It likely becomes a business decision of cost/benefit.  Unlike U-tubers who do their off the cuff tests with possibly uncalibrated/uncertified equipment.  At least I have not seen any of them publish their certifications in the footnotes or in their videos.  And furthermore, they should state that their data is for reference only.

Another thing about power conditioners that I found with regards to audio performance is that power cables still matter.  I bought my Niagara and Hurricane power cord and experienced a significant improvement in sound.  No question there.  My front end components are plugged into the PC, not my amps.  So I assumed that my good, not great power cords on my DAC and preamps were good enough.  After all, for this kind of money this PC should have been the end game- or so I used to think.  When I decided to try a higher level power cord on my DAC I was both surprised and disappointed at the improvement it made to the sound of the DAC.  This higher end power cord reduced the noise floor even more as well as making the DAC sound even better.  Now I had to upgrade the power cords on my preamps and the better power cords improved the sound.  So don’t expect the power conditioner alone to do it all for you.  

Deep_333, I know what you are saying.  We had some test equipment that has to measure in the 6 ma range.  These stands were decades old but suddenly we could not get a quiet enough signal to pass final test.  My theory was that the new solar farm less than a mile away was the culprit but I will never know.  My test engineer wanted ground rods sunk next to each test stand.  I had to have some long discussions with our facilities Engineering Manager to get his approval.  He was convinced it would be a waste of effort.  The stands were working fine before, blah blah blah.  Well, the ground rod worked.  They had to drill through the shop floor and then sink the ground rods while avoiding a 400 amp service trunk.  Yikes. 

@deep_333 Your example is a very poor one. Since you quoted that only one manufacturer existed, then obviously you had no other choice to find a workaround. So it doen’t apply to current situation as you have a neumerous manufacturers providing the product. Besides power for Audio isn’t anything really special either so don’t try to make it sound something very special. It’s attitude of audiophiles of accepting subjectivity in every thing under the sun has lead to manufacturers take advantage.

Besides even though I have technical lnowledge and come from research background I don’t think engineering degree is needed to understand the need of measurements for power conditioning products which cost and arm and leg. Just common sense is needed.

@tonywinga I doubt those certifications will cost so much that power conditioners costing tens of grands cannot cover it. Besides Im not going to get into cables, thats another debatable topic.