ADD-Powr by Coherence Systems --- Power Conditioning Products

Recent research into power conditioning approaches and products brought ADD-Powr to my attention. This company, and it’s products, were previously unknown to me.

The company, Coherence Systems, is based in Santa Monica, CA. and has been in business for some time.

An introduction and general overview can be found within their ’About Us’ page:

Nordost (in 2008) purchased the QRT technology that these folks developed.

Bill Stierhout is the proprietor / owner and the brains behind the ADD-Powr product line.
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And from @sonicshading 

@sonicshading   Please follow-up with me should you want to edit or change your copied posts.

"We also listened with open minds...In a mastering studio. I was able to audition to the SorcerX4.
As I understand it: This device emits a low frequency (below 20Hz) pulse on your AC circuit as well as radiated through antenna-I think Nordost was doing a similar thing with their devices.
It does change the sound of audio being produced on the same AC circuit, but it is not a power conditioner...It is a harmonizer. It does change the sound, but that change is additive. These harmonics can can be seen on a spectrum analyzer like Izotope Ozone. If you like what it does, use it.
We are after the original source/signal...We prefer the processing to be done through the mastering chain, not our AC products-i.e. harmonic pulses that accumulate depending on how many transformers you are using - X2 vs X4

I feel using balanced power and quality passive power distribution is the best solution for A/V systems. Certainly open to what Garth Powell has developed at Audioquest too."
From @scrootable_labs :

"quickest note to add that we also initially experienced issues around extra added harmonics, as @sonicshading’s noted.. I’ve found that I’m able to replicate, manage, eliminate and/or moderate the phenomenon by placing the unit in various positions on the circuit. Initially, it was generating extra high frequencies on the transients- not really what we were after at all, but no such issue now after a few rounds of repositioning.   have been a/b testing and studying our results after multiple rounds of pitch/catch and it’s behaving more or less transparently in "regulating" other components on the chain- creates a sense of synergy, uniformity and improved imaging in our monitoring and processing setup. to sonicshading’s point, it’s also capable of producing desirable anomalies, and it’s possible to get a specific, very nice round vintage sound by placing it after other transformers on the circuit if desired- and it’s then possible to monitor those changes accurately by moving the monitoring DAC to a different circuit (both of those processes have been part of my workflow over the past few weeks.)  we’ve got a fair amount of really nice old outboard and interesting converters, but I’ve come to feel that those kinds of holistic and broad changes are most easily achieved with tweaks to the power config. I’m sure I’m in the minority on that, but I find the application intuitive and super useful. my humble two cents’ worth, and I will be trying this unit out- and also hopefully comparing vs. a Corelli or Minelli in our mastering space as well."
From @scrootable_labs :

"Here’s a set of short clips showing how the sorcer sounds in various positions on our electrical circuit- a familiar loop, first bounced from a DAW without any processing, then played through a Mytek Brooklyn DAC via a MADI-AES chain through an analog patchbay into a Brooklyn ADC:

the tone for the recaptured track is comparable with the Sorcer in and out of the system, but you can hear changes in the way the image is rendered- those shifts are mostly improvements, IMO, with a more coherent response as the unit’s engaged.

the sonic profile shifts radically when the unit is placed closer to the other gear and fed by a balanced power transformer. becomes euphonic- still desirable for certain applications, with a bit more ping on the top, a rounded kind of muscle to the midrange and extended bottom [there are another few positions I’d tried where I didn’t like the results, didn’t capture them in this specific test.]

the test is useful in also exposing some of the shortcomings with the conversion and signal path (some softening to the transients in the middle of the image, etc) but the effect is comparable using higher-end converters. I will be replicating the test in a more controlled environment with shorter HQ cable runs and improved conversion next week.
From @cohsystms :

"Hello Josh,
Thank you for your comments. I trust that you are enjoying the x4.
Indeed, especially in the last clip there is quite a remarkable sonic improvement over the first two. You used the word "euphonic".
That says it all.
You are finding the best locations for its use in the studio.
Indeed close to the electronics will have the strongest effect.
And yes, it exposes flaws in the signal path and the remedies used to correct them.
Try location near the monitor amps or in the pro tools or computer room,if there is one.
Thanks again for your support,


Coherence Systems / ADD-Powr"
From @sonicshading :


I find it interesting that you have declared your sound right, after repositioning the ADD-POWR unit. Finding anomalies with the original source material (when the ADD-POWR is in the circuit) is enough for most engineers to avoid tweaking it. I suggest using a quality spectrum analyzer to see what you declare as transparent.

I would never spend my time or my clients’ time tweaking an AC power product to supposedly affect my source material. A better Idea is to remove all gear that isn’t being used and create an acoustically sound room without serious modes. Using a mastering desk that gets out of the way and allowing speakers/monitors to be positioned without early reflections distorting the original signal.

My hearty recommendation for those interested in pursuing power distribution and how it can affect sonic qualities in a system is to start with a materials based approach. Before diving into the deep end like the ADD-POWR, you deserve to hear what different outlets/plugs sound like, then all the various platings...and using different types of passive EMI/RF absorption materials. Try listening to various power outlets and plugs that have better conductive and tight griping alloys, or shielding power cables tied to wall ground, or various passive EMI/RF absorption material. I feel this is a good starting point.

By no means do I believe everything needs to be measured to be proved, but in the case of the ADD-POWR- it just confirmed what we were hearing.

I believe Garth Powell previously at Furman and now Audioquest does incorporate Symmetrical power in their new designs. I would recommend at least listening to power conditioners made by people who have worked in this field their whole life.

You see the ADD-POWR does change the sonics of a system, and if you like it great...It is just not a proven or even fully understood technology. Not to mention- I’m not interested in radiating EM-fields in my room... I’ll keep the EM-Fields to the ones my own body produces;)

Btw- the add-powr stuff is related to other health technologies that emit EM-fields and claim to help order the chaos of complex electrical systems. curious.

It does sonically change your sound, but in our case it was not for the better..."