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November 2022

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World Premiere Review!
Audience Hidden Treasure In-Wall AC PowerCable And High Definition Wall Receptacle Review
Like a buried treasure that pays huge dividends in musical enjoyment!
Review By Rick Becker


Audience Hidden Treasure In-Wall AC PowerCable & High Definition Wall Receptacle Review


  If you're reading this review, you're either considering the installation of a dedicated line in what is likely your dedicated listening room or perhaps your home theater...  or maybe the video rig in your family room if you're seriously into watching TV. Or possibly, you've already installed a line and are wondering if this new Audience cable might be a worthwhile upgrade. In any case, I suspect you're already convinced that "everything matters" in high-end audio, especially cables. Keep reading.

Audience is one of the most respected cable manufacturers and my ears perked up when I saw the ad for their new In-Wall AC cable. It's been 20 years since I reviewed Joe Skubinski's JPS Labs Power AC In-Wall cable. He's sold miles of it and "Big Red" has remained my reference dedicated line ever since. What's taken so long for the competition to arise? Well, there is a company in Great Britain that has been around a while that sells one, but they are not a very big player in the US audio cable market.



The Construction
The cable construction consists of three 10 AWG stranded copper wires shielded with XLPE cross-linked polyethylene insulation. Black for "live" (or "hot"), white for neutral, and red for ground. (Many duplex outlets will be coded with green on the connection for ground.) In addition, there are three synthetic strands that act as spacers to improve the resistance to vibration and crushability of the cable. A single strand of bare copper wire runs through it to ground the aluminum foil shield if you really want to be obsessive. All these are covered with thick PVC that is flame-retardant, moisture- and sunlight-resistant to give it durability. And finally, the labeling on the cable reads in the direction the cable should be installed going from the breaker box to the duplex outlet.

But this is no ordinary AC power cable. The excellent construction is merely the jumping-off point for the addition of cryogenic treatment and application of their secret sauce:

"[The cable] is also treated by our proprietary EHVP, which applies extreme high voltages at specific pulse modulations, frequencies, and amplitudes in differing ratios. This very special process creates predictable paths through the crystalline grain structure providing continuity and integrity to the AC signal."


This sounds a lot like what Ted Denny does with his Synergistic Research cables that are the bedrock of my system, so naturally, I expected great things from John McDonald and his new Hidden Treasure AC cable.


If The Shoe Fits....
Dedicated AC lines running directly from your breaker box are a valuable asset, but they are not for everybody. If you live in an apartment, intend to move in a couple of years, are facing job insecurity, or have a difficult, if not impossible installation situation, this might not be for you. Unless the installation (and hence the removal of the line) is fairly straightforward, you can't just pack it up and take it with you like an amplifier.

The degree of difficulty of installation varies widely. My dedicated listening room is what normal people have for a living room on the first floor of my home. The basement below has exposed floor joists so I merely had to drill holes through the joists and run the cable from my box to a location near my rig. I was careful to avoid other AC house lines as best I could. In one instance I crossed a house line at right angles and spaced the Hidden Treasure a few inches above the pre-existing line. I had the JPS Labs cable connections performed by a licensed electrician, but I've since learned how to install circuit breakers and connect lines in the breaker box by watching YouTube videos. More people in my town die from gun violence than from electrocution, but you will have to decide whether you can develop the skill and confidence to do your own installation. When in doubt, call an electrician or perhaps a home theater installer.

The Audience Hidden Treasure In-Wall AC Power Cable comes in two forms. Most will probably use the version with flexible PVC sheathing that can be used in-wall or strung through your exposed floor joists. There is also a version with flexible interlocked aluminum armor if outdoor installation or your local electrical codes require it. In homes without basements, it may be possible to run the line outside under the eaves of your roof. Again, check your local codes and consult an electrician about this to learn what may be possible for your particular situation.



The cable measures 0.72" (18.3mm) in diameter, so I used a 13/16" Irwin Speedbor paddle bit to easily cut slightly oversized holes to feed the cable through the floor joists. (This bit should cost less than $5 and will quickly cut through floor joists.) With 10 gauge wire you are good for 30 Amperes so I installed a 30A breaker. Unfortunately, my breaker box was full, so additionally I had to combine a couple of 15A circuits on a Tandem 15A breaker to free up a slot for the new 30A breaker. For those who may need it, the Hidden Treasure In-Wall cable can also be used for 240V installations as well as the more common 120V house wiring.


Tandem 15A & 30A Breaker


Upstairs, I drilled a pilot hole near the baseboard where I wanted the Audience cable to emerge in my dedicated listening room and pushed some white 12Ga. wire through it so I could easily spot it among the floor joists in my open, unfinished basement filled with the treasures of many decades, including my father's tools — some of which date back to the 1940s. I measured 35' to the breaker box, allowing for twists and turns through the holes. I also allowed for the cable to be stapled to the wall by the box as you see in the photo below. At the other end, I planned on screwing the junction box for the duplex outlet to the floor, rather than a more complicated (and permanent) in-wall installation. Either way meets the code within my area, though you should check with an electrician in your area to see what is allowable where you live.



In the above photo, the thick red cable on the left (Big Red) is the JPS Labs In-Wall AC line. The thick black cable just to the right of it is the Audience Hidden Treasure In-Wall AC line. They do not actually touch each other. The modest-sized breaker box is attached to a thick plywood sheet attached to the cinder block wall. Unfortunately, the builder didn't anticipate the home ever being owned by an audiophile with the need for multiple dedicated lines.


The Review Protocol
I sent John McDonald, President of Audience, the URL to my JPS Labs review and heard back in just a few days. He must have liked my comparison of the JPS cable to a standard Romex dedicated line. In addition to the AC cable, he offered to send me their Hidden Treasure High Definition Wall Receptacle to terminate the dedicated line. How could I refuse?



John takes presentation seriously and this Hidden Treasure came in an elegant cardboard box with a plastic window that foretold the quality of the duplex outlet within. A careful comparison with Furutech photos on the Furutech website indicates a very strong similarity, save for the large external rectangle on the side of Furutech models. John said they do not outsource their product from them. Regardless, the Hidden Treasure is the finest, most elegant, and beefiest duplex I've come across. It uses high-quality copper plated with Rhodium and provides the tightest grip of any high-end duplex I've ever tried.

They are also conditioned with the EVHP voltage treatment given to the AC cable. Additionally, nanoparticle damping material is applied to reduce micro-vibrations as well as EMI and RF interference. The attention to detail is exquisite, a term I never thought would be used to describe a duplex outlet. Details like labeling the ground connection, the four holes for connecting the power wires and looping through to connect another duplex in series, and raised letters in the thermoplastic Nylon identifying the sides for the black (hot) and white (neutral) wires — the plating of the metal parts was like jewelry. Excellence!



The quandary I faced was that I could not directly compare the Hidden Treasure AC cable with the JPS Labs cable. Big Red had a high-quality quad outlet that does not permit the substitution of conventional duplex outlets. Short of cutting off the quad outlet box and attaching a box that would accept one or more duplex outlets, there wasn't much I could do except hope that the differences in sound quality were large enough to overlook the differences in the AC inlets. I could, however, do a direct comparison of the Hidden Treasure with the Synergistic Research Purple duplex using the quad box on my Romex 20A dedicated line. In the photo below you see the Purple duplex at the top with the Hidden Treasure below it. Both are rated at 20A, 125V.



At about 30 hours of burn-in, I compared the Hidden Treasure duplex on the 20A Romex line with the JPS Labs In-Wall 30A line with its captive quad outlet. The sound quality was just about the same. If this were the end of the review of the Hidden Treasure duplex, I would say it is an outstanding bargain, given that it equaled the sound quality of the JPS cable without incurring the cost of that expensive cable. $200 for the Hidden Treasure duplex, plus the much more affordable installation of the Romex line, and BOOM, you're done. (Though I've said before, if I had it to do over again, I would install 10Ga. 30A Romex wire instead of the 12 gauge 20A.)

But we all know 30 hours is still minimal time for most cable burn-in. Surely there was more sound quality to emerge. I had done some direct comparisons with the Synergistic Research Purple duplex at this point and found some noticeable differences, but given the short burn-in on the Hidden Treasure, it would be misleading to mention them here. I removed the Hidden Treasure duplex from the quad box and installed it on the end of the Hidden Treasure In-Wall dedicated line for further burn-in, letting them run 24/7 with intermittent listening sessions. I used a metal box designed for outdoor use along with a stainless steel top plate that looked rather spiffy. This will eventually be screwed down to the floor to meet code and facilitate the inserting and removing of power cords from the almost vicious jaws of the Hidden Treasure duplex.


Outdoor Duplex Box With Stainless Steel Cover


With fifty hours on the Hidden Treasure cable and duplex combination, I ran more comparisons. My rig was set up with Synergistic Research Atmosphere Excite SX power cords ($2495 each) and a loom of their Foundation interconnects ($699 for 1-meter pair) and speaker cables ($749 for 8' pair), not the new Atmosphere Excite SX interconnects and speaker cables I recently reviewed. The two power cords in the photo above supply my eight-outlet Synergistic Research power conditioner and a Synergistic Research power strip that feeds my subwoofers.

The Hidden Treasure combo was giving me higher quality sound than either the Synergistic Research Purple duplex on the Romex line or the JPS Labs AC line with its captive quad head was giving me — even when I had been using the much more expensive Synergistic Research Atmosphere Excite SX loom before this review began. Given the difference in price and sound quality of the Foundation and Atmosphere cables, this is a huge breakthrough. Though it begs the question of how good the rig might sound if I re-inserted the Atmosphere Excite SX cables. (We'll get to that in a moment.)

The improvements were across the board. Tighter and more tuneful bass.Finely resolved cymbals. Instruments had more solidity and were more specifically located on the soundstage. Improved resolution throughout. Image size and heights were more correct. Micro-dynamics and dynamic shading were more evident. I could go on, but the bottom line was clearly in sight at this point. There were a couple of additional variables which had to be sorted out before drawing final conclusions.


Sorting The Variables
After two weeks of continuous burn-in, and to establish a baseline, I spun through my compilation CD listening to the Hidden Treasure dedicated line terminated with the Purple duplex in the box capped with the stainless steel cover. The music was very good in most respects but a few qualities were missing from what I was accustomed to before this review began.

Next, I replaced the Purple duplex with the Hidden Treasure duplex and retained the stainless steel cover. The music was more transparent, more dynamic and the soundstage moved closer, but still was a bit behind the plane of the speakers. There was more inner detail, particularly on cymbals, and a trumpet had more bite. The prominent bass line on Springsteen's "57 Channels" had exemplary PRAT (pace, rhythm and timing), causing my toe to keep time with it. The Chinese drum cut exhibited more realistic timber and greater resolution. On the cover of Elton John's "Daniel" by Wilson Philips, the improvement was very evident in the shimmering cymbals, greater PRAT, and improved resolution. There was a greater separation of instruments in this ‘wall-of-sound' recording and the three female vocalists were more easily identified. The transparency was still below what I had been accustomed to prior to this review, so I pressed onward.

In this next round I replaced the stainless steel cover with a Synergistic Research Carbon Fiber Duplex Cover — a single duplex version of the double duplex cover I had been using on my quad box with the Synergistic Orange and Purple duplex outlets prior to this review. Replaying "Daniel" the soundstage became more accurately defined with greater separation of the singers from the instruments behind them. There was an impressive jump in transparency yielding more presence in the room as if more light had been shed on the soundstage.

On Springsteen's "57 Channels" the distant refrain far back and to the left, one of my key signifiers, was excellent, as were the overdubs at the end of the song. On the Chinese drum cut the soundstage was more forward and this was the best I have heard my vintage Tekton Design subs perform. The vibrations were felt in my chest. And on James Taylor's live rendition of "Steamroller Blues" there were noticeably greater dynamics (suggesting a lower noise floor) and with the single high piano note at the stillpoint just before the guitar solo, the piano note sounded exceptionally real.


With Synergistic Research Carbon Fiber Cover


With the combination of Hidden Treasure In-Wall cable, duplex outlet, and Synergistic Research carbon fiber cover I was getting the best sound ever out of my rig. But let me advise you that I had to fine-tune this combination by adjusting the screw holding down the Synergistic cover. Too tight and it over-damps the sound. Too loose and you're not getting the sound quality that you paid for. Just snug seems to be about right.

The next step was to add a U-shape piece of Stillpoints ERS paper inside the junction box beneath the Hidden Treasure duplex. This material absorbs EMI and RFI and works very well inside the chassis of some of my components. In this instance, I couldn't hear a discernable difference. I'll leave it in for a month or so and then remove it. Often times there is greater recognition of a tweak's benefit when it is removed, rather than when it is installed. But I don't have high hopes in this instance.

The last step was to substitute the reference Synergistic Research Atmosphere Excite SX interconnects and speaker cables for the Foundation cables. Listening to Buddy Guy on electric guitar the music was more relaxing. There was even greater resolution now, leading to shorter decay of notes and less bloom around them. Overall, the sound was a little dryer. I found myself leaning back and relaxing, using less brain power to interpret the music and lyrics, rather than leaning forward into the music and concentrating a little harder. Springsteen's "57 Channels" was the best I've ever heard with a very taught bass.

The Chinese drum cut revealed more transparency and higher resolution, again, a best-ever performance. At the end of "Steamroller Blues" the audience clapping and the ambient noise of the venue was very real. The soundstage extended way out into my front yard. On "Daniel" the three voices were so highly resolved that I could easily separate the singers in this three-part harmony, something that has always been difficult at best. The strings on Zoltan Kodaly's "Glass Bead Game" were very believable and sweet. And lastly, the tighter sound and less bloom of this combination made BB King and Eric Clapton sound more real and in person on "3 O'clock Blues."


When it comes to calculating the value of this product, there are variables that significantly affect the cost, once you have determined that it is feasible at all.

· What is the distance from the breaker box?

· Can it be run through the floor joists easily, or will it have to be routed through walls?

· Or outside the home?

· Is this a DIY project or will I have to hire professional electricians or installers?

· If your house is being built, the builder will likely require that he do the job with an upcharge.

· Can I easily take the cable with me if I decide to move? Or sell it later if a better one comes along?


So the cost will be all over the map, depending on your particular situation. But cost is not value. As I've shown above, the Hidden Treasure In-Wall cable can make a very significant contribution to the sound quality of your rig. The cost of the cable and the duplex outlet in my situation was around $1000 plus $149 for the carbon fiber cover and maybe $10-$15 for the 30A breaker and the outdoor junction box. So maybe $1200 in material for a 35' run. That's less than half the cost of a 1m pair of interconnects in my rig, or the cost of two pairs of Foundation interconnects.

Yet the dedicated line will improve the sound of your entire system. And it will likely serve you for the rest of your tenure in your home. It's not like other cables that are constantly improved every few years. And it is a lot less than a typical component upgrade you are likely to make, not to mention an expensive upgrade of your speakers. In fact, this review has shown me that once again I have not fully discovered the full sonic quality of the Kharma speakers I bought back in 2003. Most everything but my FM tuner and CD transport has been upgraded over that time period, and even those two items have received substantial tweaks along the way. It's taken twenty years for an exceptional preplacement for my dedicated line to arrive.


In the grand scheme of a serious audiophile system, a dedicated AC line is an often overlooked component. If it is at all feasible, it shouldn't be. At the very least, one of the more expensive audiophile-grade duplex outlets such as the Audience Hidden Treasure reviewed here should be installed as your primary outlet. That alone will raise your sound quality far above spec-grade or hospital-grade outlets.

Beyond that, your choice of in-wall cable is dramatically reduced. I've been smug about having the JPS Labs In-Wall cable as my reference for the past 20 years. It has served me well, but time marches on. John McDonald has introduced a new kid on the block — the Audience Hidden Treasure In-Wall AC cable. In addition to the superior construction, Audience applies technology that is usually found in cutting-edge power cords, interconnects, and speaker cables and runs it all the way to your breaker box. It benefits your entire system and reveals sound quality from your components that you didn't know were already there.

Once installed, you don't see it. It's like a buried treasure that pays huge dividends in musical enjoyment and I give it my highest recommendation. I truly hope it is a feasible addition to your system.




Sub–bass (10Hz – 60Hz)

Mid–bass (80Hz – 200Hz)

Midrange (200Hz – 3,000Hz)

High Frequencies (3,000Hz On Up)



Inner Resolution

Soundscape Width Front

Soundscape Width Rear
Soundscape Depth

Soundscape Extension Into Room


Fit And Finish

Self Noise
Emotionally Engaging

Value For The Money




Type: Premium audio tweaks for AC power
Hidden Treasure In-Wall AC Power Cable: $300 for 10 feet and $660 for 30 feet.
    Each additional foot is $22.
    Aluminum armor-clad BX version is priced the same.

Hidden Treasure High Definition Wall Receptacle: $199




Company Information
120 N. Pacific Street
San Marcos, CA 92069

Voice: (760) 471-0202
E-mail: info@audience-av.com
Website Audience-AV.com  
















































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