April 2026

World Premiere Review!
Heartsound Audio Holostage Review: Scientific Voodoo Or Genuine Upgrade?
Hands-on evaluation of sonic impact, transformative sound, and where Holostage fits in your audiophile journey.
Review By Rick Becker

   It was pure chance that I stumbled upon Heartsound Audio's Holostage. I'm not an avid reader of audio blogs, but occasionally an e-mail with a Weekly Recap of the Audiogon Discussion Forum will slip past my email filters. The subject was actually the Nirvana Chronos, which I had previously heard at AXPONA in 2025 and subsequently reviewed very favorably. People wanted to know if the Heartsound Holostage was similar or as good, since it was considerably less expensive. I fired off an inquiry.

Kristine Tetrault, founder of the company in 2021, replied shortly with an offer to send me a review sample. The Holostage is sold in sets of four blocks for $1000. It arrived via Priority Mail from Concord, NH, which is too far inland to catch any scent of saltwater. Inside the Flat Rate USPS box was a black cardboard box of the kind you might expect a gift from Macy's to be wrapped. Inside, the four Holostage blocks were individually wrapped in silk-like pouches secured with a drawstring and decorated with clefs and notes of various lengths, pitches, and sequences. Matching wrapping paper was used to further stuff the box. It was a heartwarming touch.

The blocks looked like generic molded plastic with the top held down with a Philips head screw at each corner. A treble clef and the company name in a subdued color are printed on the top. They each weigh 9.28 oz. (263 grams), and measured 3.25" square by 1.25" thick, plus another 0.1875" (3/16") for a protective compressed felt pad at each corner on the bottom. They reminded me of the solid maple blocks I used to play with at my grandfather's house in both size and weight. I imagine you could easily drive over them with your SUV and do little more than scuff them. Being black, modest in size, and tastefully branded, you can place them anywhere in the room without detracting from your décor.

The website gives suggestions for placing them around the room, starting with keeping them about 4' off the floor:

In no specific order, I tried all these suggestions before they had been posted on the website, and came up with some differing observations, which probably reflect my personal taste in how I want music to sound in my room, and my personal bias in which sound qualities I listen for. Regardless, it is easy and fun to try various placements, and your preferences will likely differ from mine—so have at it!

Getting Started
My rig is approximately a 9' equilateral triangle with the speaker baffles about 56" out from the front wall behind them. My equipment rack is against the front wall, slightly to the right of the right speaker. With the listening triangle aligned on the long wall of the roughly 20' x 40' room, the side walls were far to the left and right of their respective speakers, largely eliminating side wall reflections. The Nirvana Chronos had been removed to my back office for several days to allow its effect to dissipate completely. Likewise, I removed the Synergistic Research Vibratron, as it is not a widely known tweak.

A couple of results in placement stood out in particular. I started with just two of the Holostages, placing them on the LampizatOr DAC and the Synergistic Research PowerCell 14. Whereas the effect of the Chronos is perceived almost immediately when it is introduced to a system, the Holostage ramped up gradually over the course of a couple of minutes, and like the Lessloss BlackGround Power Base and BlackGround for Speakers, continued to build up over the course of several days. My initial impression was that the two Holostages had about the same effect as the demonstration with two Chronos at AXPONA. Since I had only one Chronos to review at home, the two Heartsound Audio Holostages had an even more powerful effect in my listening room.

I then added two more Heartsound Audio Holostages slightly behind the listening chair, several feet out from each side of my head, and three to four feet above the floor. The effect became even stronger, easily outperforming the presentation at AXPONA 2025 with two Chronos. Adding the Synergistic Research Vibratron was easy—just bring it back into the room and set it in its usual spot. Doing this made the digital music even more analog-like, hence more relaxing. Since the LessLoss BlackGrounds require cabling, I didn't bother to reintroduce them during my critical listening. Likewise, I again removed the Vibratron for the duration of the review, except when noted.

The Listening
After letting the Holostages settle in for five days, I sat down with my very familiar compilation CD for some critical listening. The resolution had improved even more with very fine edges to notes, whether quick or sustained. There was no smearing in comparison without the Holostages. This lack of smearing revealed the roll-off of high frequency from cymbals with the Acora Acoustics QRC2 loudspeakers driven by the Manley Mahi tube monoblocks. With greater resolution, there was less noise, and lyrics that previously faded into that noise became more intelligible. With greater resolution on heavy bass notes, there was more slam, and I could more readily feel vibrations in my chest.

Violins on well-recorded string quartet music were spectacularly clear, and the bloom and decay of the electric guitar from Buddy Guy were clearly enhanced. Pianos sounded more like real pianos with micro-details of hammers on strings and the working of pedals becoming more evident. Harmonicas, which would normally come across in blaring notes, became much more complex, revealing the attack and sudden decay, as well as the subtle and quick tongue work. At the other end of the spectrum, female vocalists with sultry or smoky voices, such as Nora Jones, became easier to comprehend.

The increase in resolution brings with it not just the clarity and inner details mentioned above, but also the gift of spatial recognition. First of all, the notes themselves have more body and physicality. Secondly, in soundstage presentation, it more precisely positions the players on the stage, and provides sufficient resolution allowing you to follow an instrument's line by keeping it distinct from the other instruments. This was particularly evident on the American Folk Blues Festival '70 with various combinations of black blues musicians. The improved resolution also facilitated comprehension of their ethnic dialects. In larger, orchestral music, the layering and positioning of different instruments were noticeably more effective.

Three days later, the music was even more highly resolved. The hall sounds of live recordings became more easily recognizable. Bass became more true to the instrument, and drums were revealing the tonality of the skin rather than just the body of the drum. The attack of the notes more readily identified the instrument, and the body of notes had more bloom and decay, indicating the noise floor had dropped further. The sibilance on Paul Simon's "Diamonds on the Souls of Her Shoes" was noticeably more controlled. Music had more flow; my foot, cantilevered over my other knee, kept on bouncing.

Most importantly, the space of the actual recording session, whether it was a live recording or one crafted in a studio, was experienced as more real or believable in my listening room. With increased believability, the mind could relax and enjoy the musicality and flow of the music itself.

Another five days in, I re-listened to parts of my compilation CD and heard no discernible differences, so I reintroduced the Chronos along with the Holostages. There were small improvements. Cymbals were a little more resolved. Bass had a little more timbre, whether it was a string bass or a drum kit. It seemed more lifelike, more analog, and more natural. But all this was a small difference, comparable to the effect of tubes warming up in your system.

When I removed the Chronos (whose effect dissipates fairly quickly) and immediately replayed James Taylor's "Steamroller Blues", the smooth, analog, natural veneer disappeared somewhat. When I tried the same trick with a Zoltan Kodaly string piece, the strings sounded a little more real with more bite and transparency when the Chronos was removed. I then removed the Holostages, too, and heard little difference. I had forgotten that the effect of the Holostages dissipates more slowly than the Chronos.

I left both the Chronos and Holostages out of the system, and the next day replayed my compilation CD. Twenty-some hours later, the system sounded rough. I added just the Chronos and listened to cuts 1 to 5 again after a 15-minute warm-up. The system came back to life again with all the good qualities that the Chronos brings to a system.

I then installed the Holostages and removed the Chronos, and let it settle in for two and a half hours while I took a break for dinner. The transparency was just about the same, but there were further improvements with such things as a stronger bass, a little better resolution and timbre on the drum cut, better cymbals, great audience cheering, more discernible backup singers, and a more convincing "you are there" feeling without being abrasive. Keep in mind this was one Chronos versus four Holostages.

Hit The Road, Jack!
As with the Nirvana Chronos, I tested the Holostage in my Volvo station wagon equipped with the stock multi-speaker radio/CD system. Using my familiar compilation CD, I found significant improvement in sound quality, primarily in resolution across the audible spectrum. However, don't expect miracles. It still does not compete with my rig in the listening room. But with very little effort, the Holostage can make your road trips more enjoyable.

Speak To Me Of The Voodoo 
No, I didn't back out the screws and peek inside. Like many tweaks, the technology of the product is proprietary to prevent proliferation (read: unscrupulous duplication). I also don't want to trigger a race to the bottom in pricing. What seems evident is that the Holostage affects the RFI in the listening room and the EMI inside the components. While this is much like the LessLoss BlackGrounds, they do not plug into the AC circuit or the electrical ground. And from what I am unable to disclose, the technology is different from the Nirvana Chronos. The form factors make this obvious. In its brick-like container, it's also not likely that it has anything to do with the Earth's Schumann resonance. Their website hints that it has something to do with chemistry, likely minerals that filter out RFI/EMI. From time to time, I hear stories about minerals and crystals being used in cables and grounding devices. In fact, Heartsound Audio offers an affordable Ground Box similar in construction, but larger than the Holostage.

Kristine added that she "actually worked with an audiophile ‘think tank' that included nano chemists, a mechanical engineer, a nuclear engineer, electricians, professors, three doctors, and two lawyers." Several years of back-and-forth testing went into the development of the Holostage. But that's about all I've got for you.

Additional Positioning
At one point, I put a Holostage on top of each Acora speaker and left another on the DAC and power conditioner, slightly behind and to the right. After it settled, the music was weighted more to the front of the room, and the soundstage was more shallow, compressing the musicians.

Then, I left a Holostage on each speaker and put the other two behind me, off to each side of the chair. The soundstage became deeper, and I felt I was positioned at the front edge of the stage. I also tried placing a Holostage at the speaker binding posts, along with one each on the DAC and power conditioner. This was the least satisfactory positioning I tried, but again, with your room and your speaker positioning, there could be vast differences in results, so play around.

Value
The results I achieved with the Holostage were icing on the cake of a well-sorted-out system. They were also results comparable to what I hear from much more expensive systems at the four shows I attend each year. For most audiophiles, the journey is one of incremental steps. The Holostage brought me closer to that elusive experience of being there, right at the performance (or in the mixing studio), that is only sometimes achieved with components that cost tens of thousands of dollars, or even far more. It is in the league with products from LessLoss, Synergistic Research, SteinMusic, ERS paper, a few magic solutions, and dozens of footers that magically improve the resolution and palpability of your music. And often for much less cost.

Moreover, if you ultimately decide to spend large for an expensive component on your wish list, I'd wager the Holostage will benefit it as much as my more modest components. In direct comparison with the Chronos, the Holostage produces a higher degree of comparable improvements at 40% of the cost. This should make it a viable addition to the rigs of a lot more audiophiles. If, for some reason, the fine-tuning offered by the Holostage doesn't meet your expectations, there is a 100% money back no questions asked 30 day guarantee. That puts the ball in your court.

Summary
Kristine Tetrault has leveraged her scientific background with a clique of like-minded chemists and "other professionals in the scientific and academic world" to develop another entry in the category of Voodoo audiophile tweaks. I've reviewed far more than my share over the past few decades, and the Holostage is up there among the best. My rig is full of these adventurous products. Typically, these tweaks do not compete with each other, addressing different weaknesses at different points in a system. They tend to be symbiotic or complementary, and are not rendered obsolete with the acquisition of new components (except for fuses). Hence, they retain their value. It's not like you're buying new speakers and selling off the old ones at half price.

If you're early in your audiophile journey, I'd say get the basics down first. Discover what your preferred acoustic preferences are, and don't neglect the importance of your AC feed and power cords. But if you've got your system balanced and sounding pretty good, and are looking for the next big step for around a grand, the Heartsound Audio Holostages will likely give your entire system a boost in resolution, inner detail, and musicality that you didn't think was possible from your current components.

I am very enthusiastic about welcoming them to my arsenal. My music has never sounded better.

Which reminds me... they come with a warm Thank You card to match the inner wrapping paper. Very thoughtful and appreciative.

Specifications
Type: High-end audio tweak
Price: $1000/set of four
Warranty: 100% money back, no questions asked, 30-day guarantee.

Company Information
Heartsound Audio
The Concord Community Arts Center
40 Thorndike Street
Concord NH 03301

Voice: (603) 731-9329
E-mail: heartsoundaudio@gmail.com 
Website: HeartSoundaudio.com