Game Changing Tweak

One other thing ADD-Powr says in describing their technology:  
"

• They generate and propagate low frequency signal information to affect harmonic change to audio signals.  

• They super saturate the AC line voltage with harmonics to affect a 1 to 5% increase of the voltage peaks delivered to the power supplies of system components."

Why exactly would you want to increase voltage peaks?  Stable voltage is extremely desirable, peaky voltage not so.  The vast majority of PQ problems are voltage related, either a sag or a surge, and those can mess mightily with electronics.  Also, how does super saturation with harmonics increase voltage?  Harmonics are undesirable.  Now, if you are doing PF correction, that will slightly lower voltage by lowering current flow, but they also specifically say, "

     ADD-Powr products are

    Electronic harmonic resonators.

    They are not AC power line conditioners".

Honestly, the more I read this on this site the more it screams Snake Oil.

@pragmasi
Your scenario doesn’t account for the fact that the distributors always have a money back guarantee and always give sufficient time to evaluate a product and return it if not satisfied. If we had to be persuaded of the theory before we buy a product, none of us would own a high definition TV model because we sure don’t know how it works. Most airplanes would be empty if the airline had to explain to all the passengers how it works. We try things, if they work we keep them, if they don’t, we return them. If there is a life or death probability, we let someone else try it first 😀

These marketing stories are just that, stories. Which is not to say there aren't improvements from using this stuff. Very likely there are. Its just to say the improvements are not for the reasons we're being told.

In fact the one thing I am most certain of is that they are NOT for the reasons we're being told.

Why am I so certain? Because a thin coat of Total Contact on the outside of a wire, AC or signal, makes no difference,  makes all the same great improvements people are talking about, and for certain it is not generating or saturating anything, and absolutely is not doing anything active. All its doing is somehow improving transmission. Somehow. We don't know.

People hate not knowing. Lotta people rather believe utter nonsense than admit WE DON'T KNOW! Oh, the horror!  

Me, I kind of welcome the not knowing. Because the minute you can convince yourself you know why, then you stop thinking about what if? Look around. Look how often it happens. Look at all the people trying to buy cables, and all kinds of stuff, based on what are nothing more than cockamamie stories. Only they won't call them that. Oh no. That's a big part of the delusion, to call your cockamamie stories theories, principles, facts, measurements, anything but what they are: narrative. Fanciful tales. Fables. Myths. Stories. 

The people screaming snake oil are no better. They know even less. At least the people who pretend to know why might actually bother to try the stuff and listen and use it and maybe learn a thing or two some day. The snake oil people, what they are really saying is their mind is made up, you're all suckers, and no way they will ever even try to listen and learn. They're the lowest of the low. They truly need a new hobby.

Of course, none of this really matters - unless you really are interested in building an exceptionally fine sounding system. Because then if you are serious about it you will go and listen and keep trying and learning, and maybe even one day realize that just like mahgister keeps saying the tweaks matter at least as much as the components.

Go and listen. You will see.

@bemused--  You wrote:
"From perusing the web site, ADD-Powr is appears to be about increasing "energy", or the voltage of the audio signal through the generation of harmonics on the reference supply that are too low in frequency to be filtered away by the component power supply. They more or less resonate with similar frequencies in the audio signal. If the fundamental signal is low enough, then its resonant affect will be evident throughout the audio band. The driving fundamental must be a complex function composed of sines and cosines in various phases - that is the Fourier series. Or...perhaps it can be simply be a square wave!

That explanation makes sense."

It does not make sense to me.  Can you explain it?  What frequency levels are we talking about, exactly?  Power comes in at 60Hz.  What low level AC frequency will resonate through a DC power supply?

@millercarbon--

Please refrain from obscene generalizations about people. When I say something seems like snake oil I am most certainly NOT saying that my mind is made up, that everyone else are suckers, and that I am not going to listen and learn.

What I AM saying is that when there is no rational basis to accept a manufacturer's claim as to how something works, and they provide not a shred of what should be easy-to-provide corroborating measurements to demonstrate effectiveness, it makes me highly skeptical.  There are a thousand tweaks out there and my time is limited, especially I am going to spend it listening to things that have a reasonable chance of making a difference. Especially regarding improvements from AC side tweaks, which have nothing at all to do with the musical signal.   Unless your power quality is terrible, AC side stuff just isn't going to make a difference.  Running your system off a quality UPS will give you perfect sine wave power, stable voltage, and no harmonics.  Problem solved.

For goodness sake, would you not be skeptical of, say, an amplifier designer who says their amp sounds better because it's inhabited by quantum level musical pixies?

Hey, if someone else hears a difference, more power to them, though, with the ever present caveat of awareness of confirmation bias.  If you don't do double blind testing, how do you know you actually heard it?  By all means, go by what you hear - I certainly do - but don't you want to be certain that you really heard it?