SKU: 83583840378

Heartsound Audio Holostage Room Treatment Device - 1 unit

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Description

Heartsound Audio Holostage Room Treatment Device - 1 unitHeartsound Holostage Room Treatment Tweak After the Munich High End Show in May 2024, we had the good fortune of visiting our good friends Rhapsody Audio in the Netherlands for a few days of R&R and immersion into all things music & hi fi. Harry and Michael are very well known in Europe for having an ability to create immensely satisfying sound systems, as their long list of sophisticated satisfied clients can attest. Their reputation and abilities

Heartsound Holostage

Room Treatment Tweak

After the Munich High-End Show in May 2024, we had the good fortune of visiting our good friends Rhapsody Audio in the Netherlands for a few days of R&R and immersion into all things music & hi-fi. Harry and Michael are very well known in Europe for having an ability to create immensely satisfying sound systems, as their long list of sophisticated satisfied clients can attest. Their reputation and abilities are a result of have a great ear, immense musical knowledge, experience in recording studio environments and decades of experience with high-end audio. During this time, after playing a mesmerising Sarah Vaughn track (Lost records label – Live at Laren Jazz Festival 1975), Harry pulled out this box of non-descript little boxes and said with a wry smile ‘guys, you have to hear what these little babies can do”.

What’s in the box Harry?
George, I’m not sure exactly but have a listen.

At this stage, I’m feeling a bit strange. You see, the high-end world is filled with tweaks, enhancement and optimization devices that are to be very frank… crap. During the many years of my involvement with the hobby, I have been shown, tried, tested & auditioned literally hundreds of these devices and I have found only a handful to have serious scientific and sound quality demonstratable value. In fact, I get upset when I witness the way the audiophile community gets taken for a ride by scrupulous unethical operators selling their latest version of ‘snake oil’.

So imagine our surprise when Harry (a man I deeply respect) pulled out these boxes. Well, you have probably guessed what happened next which is why I’m telling you about them. We simply kept playing the same track, beginning to end while adding more of these boxes to different parts of the room and listening for their effects. I can say that the Nirvana team was very impressed and immediately made contact with Heartsound Audio in the USA.

Founded in 2021 by Krissy Tetrault, Heartsound Audio is a US based company that manufactures a device called the ‘Holostage’. There is a real science behind this product with many chemists and academics collaborating and contributing to the technology over many years.

Place these little black boxes in your listening space and enjoy an expansion of your soundstage, increased dynamics and perceived lower noise floor. Many describe them as creating an ‘ease’ in the music, removing the ‘tension between the notes’ which results in a more fluid, flowing, less-mechanical presentation of the music. In some ways, Holostages bring fun and wonder back into the hobby – tweaks to customise and improve your emotional engagement. They are available to try with a money back guarantee and if you like what they do they are not an expensive upgrade.

No clumsy wires, batteries, or chargers necessary. These devices are ready to enjoy out of the box!

When we play music, the sound waves necessarily set the whole room and everything in it vibrating. We all know this, and do all kinds of things to alleviate it, with absorptive panels, diffusion panels, and so on. We also use springs, pointy spikes & cones, granite slabs, sorbothane and other materials to deal with these resonant energies. Holostages perform sound field isolation by working electrostatically in a way that allows the sound field to vibrate with greater isolation from the rooms own acoustic environment.

Sceptical? Just try them and in our experience, they will probably stay in your system!

Many who are discovering this new technology are describing the Holostage as the most effective and satisfying tweak they’ve ever experienced.

How Do They Work?

The exact content inside each Holostage is proprietary however we do know that the device operates using the principle of piezoelectricity, which is the electric charge or ion discharge that accumulates in certain solid materials such as crystals & ceramics in response to applied mechanical stress. The piezoelectric effect is utilised in a few applications that you may be familiar with. Let’s consider a type of cigarette lighter for example. By pressing the button you place stress on a piezoelectric crystal that charges a capacitor, that when fully charged suddenly discharges the spark that ignites the butane.

There are some materials which exhibit this piezoelectric ability. This means that when subjected to a mechanical stress, they can produce an electrical current or release ions. Krissy Tetrault studied the documents and white papers that resulted from many years of research on the topic of piezoelectric ion proposition and simply selected a mix of materials that have these properties. The contents of the Holostages include a complex matrix of piezoelectrically active crystals and Graphine nanotubes which generate an electric current and discharge ions when a stress force is applied to them.

What is the stress force you may be wondering? It’s the sound wave energy moving through your room! When the sound waves interact with the Holostage boxes, the forces trigger the release of ions into the surrounding space. The presence of the ions has an effect on how the sound energy moves through the air. The electrostatic relationship between the sound waves, which are effectively vibrating air molecules and the ions within the air molecules has this effect where the sound travels with a greater ease and seems to be more isolated from the effects of the room.

Ions Affect the Speed of Sound

Cations are positively-charged ions (atoms or groups of atoms that have more protons than electrons due to having lost one or more electrons). Anions are negatively-charged ions (meaning they have more electrons than protons due to having gained one or more electrons). Cations are also called positive ions, and anions are also called negative ions.

Identifying the composition of a solution using acoustics remains a challenge. It is known that for low salt concentrations the speed of sound in water increases linearly with the concentration of the electrolyte, but the contribution of individual cations and anions is relatively unknown. However, experiments have been completed where the concept of intrinsic sound speed Ai was introduced to quantify the contribution of ions to the speed of sound. The results proved that cations increase the speed of sound in water whereas anions decrease the speed of sound. Hydration layers around the ions play a major role. Because cations have a hydration layer thicker than that of anions, their contribution to the speed of sound is larger than that of anions.

Experimental data on salts not used to determine the contribution of individual ions are in quantitative agreement with the predicted values. This method has also been applied to various systems containing small quantities of ions, molecules, or particles in air, also verifying that cations increase the speed of sound, and previously unexplained data in the literature has now been explained by these experiments. From the perspective of listening to an audio system, we can also now claim with certainty, based on these experiments that the presence of ions in your listening space influences the way the sound energy travels through and behaves within the medium.

Suggestions For Placement

Begin by placing Holostages in each corner at approximately four foot in height.

The devices can and should be moved around the listening room until optimal performance is achieved.

Clients have made the following observations:

  • Place around the room for a larger sound stage and greater ‘ease’ of sound.
  • Place on speakers for an increase in speed and accuracy.
  • Place near/on components for an audible reduction of noise and improvement of dynamics.
  • Place on power supplies for an overall improvement of dynamics and a drop in the noise floor.

Reviews

Millercarbon’s The Audio Files, 2023

Spoiler alert: Holostage sound field isolators are the craziest, coolest, most mesmerizingly effective tweak I have tried yet. And I have tried a lot of tweaks! Small, versatile, and highly effective, Tetrault Audio’s Holostages are a revelation, and highly recommended.

Read Review

Testimonials

I used to be a power cable and interconnect sceptic. Now, it’s a ‘must have’ to realise the potential of your system. It took me a long while to figure that out. But I’m SO glad I did!

Now, here’s a product that had me thinking, total snake oil. Voodoo witchcraft!

Even my cynical audio buddies and I thought, ‘No way’, not possible. Snake oil.

Enter, the passive Heartsound Audio Holostage blocks. If your system is high resolution, putting 4 blocks in the corners of your room, will transform the sonics.

It’s immediate, and obvious. Johny Cash lp – Live at Austin Texas 1986. The vocals become more real. More 3d and more like him singing in the room. And that wasn’t all. I heard guitar strings resonate with more air and treble extension than ever before. What the???

The effect is immediate. Take them completely out of the room. Listen. What you thought was great, isn’t anymore! It’s back to 2d.

My friends and I couldn’t believe what we were hearing. This isn’t voodoo witchcraft. There’s science behind it.

Over the years we have all heard a lot of hifi accessories that claim to work. Some do. Some don’t. Some just alter the tone. They aren’t better just different.

The Hollostage blocks are the biggest secret in audio today. Totally ground-breaking. If you’ve got a high-end system, this is the biggest bang for your buck that I have *ever* heard!

Eugene, 2024

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SKU: 83583840378

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4.5 ★★★★★
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Product Reviews
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Verified Purchase
Haris
Fort Morgan, US
★★★★★ 5
Probably the best robot vacuum mop you can buy in this price range
Size: E25 Black
Its pretty solid device. Honestly its so smart that it vaccumed and mopped my bathroom and ofcourse the wet hair stuck on the wet floor wasnt vacuumed the first pass but it then waited for the second pass to pick it up when it was dry. Made my entire house look so clean its actually amazing. It actually mops and get all the corners with dust. One thing thouhh is the side brushes tend to get tangled with hair and thread but uts very snap on snap off brushes so removing the stuck hair is super easy and only sometimes happens. The suction is amazing too its very strong. It moos the floor with clean water with solution so its actually cleaning well. Overall 10/10
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 7, 2026
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Verified Purchase
Ismara
Los Angeles, US
★★★★★ 5
The best vacuum cleaner ever!!
Size: E25 Black, Size: E25 Black
⭐⭐⭐⭐⭐ I honestly couldn’t be happier with the Eufy E25. I actually own two of them, and they’ve completely changed my daily routine. After spending a lot of money trying different brands, I finally found one that truly delivers everything I need in a vacuum. The suction power is impressive, it handles pet hair and debris effortlessly, and the mopping feature actually works (not just a light wipe like others I’ve tried). The self-emptying and self-cleaning system is a game changer—it saves so much time and maintenance. Navigation is smart and reliable, and it rarely gets stuck. It covers my floors efficiently and leaves everything noticeably cleaner. I also love how low-maintenance it is overall. If you’re tired of wasting money on vacuums that don’t live up to expectations, this is absolutely worth it. For me, it has truly been life-changing.
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Reviewed in the United States on April 10, 2026
I
Verified Purchase
itsmeray
Birmingham, US
★★★★★ 3
Updated 1/28/2020 update 1/17/2020 It's been everything it was advertised to be and more. (Not)
Size: 11S
I called Amazon again today. Explained the situation and that no one from Amazon or Eufy had returned my calls as they promised. Also after replacing the battery at my own expense it ran 90 minutes again but got stuck everywhere, made this weird ratcheting type noise every time it changed surfaces and finally today just beeped at me twice and died. Supposedly that indicates a seized brush but they all spin freely. This time I just flat out asked them to look at my Amazon account and replace it, as I'm a very good customer. New one will be here tomorrow. I'll do a separate review on that one as it took me forever to find this one again. I'll also let you know if it's a refurbished unit or not. Well wouldn't you know it. I leave a nice review and a few days later, Murphy's law rears it's ugly head. Device is 3 months old a couple weeks out of the exchange warranty and the battery is shot. Runs 5 or 10 minutes on a full charge. Called Amazon to see if since I am a really long standing customer if they'd help me out. Nope but we'll call Eufy support on your behalf and they will call you. We will also call you to follow up. I've been a customer service manager a lot of years and this is where employees can kill you. This Amazon person made me multiple promises. It's been a week no call from Eufy, no call from Amazon. You just turned 4 stars into 1 and if this is all the longer the batter lasts don't bother because the replacements are $25 to $30 bucks depending on the brand. I'm not spending a hundred bucks a year on batteries and this thing should be under warranty. After 3 days I ordered a new battery and Rosie is running again but I'm no longer pleased and the next time I'll buy another brand. If if this battery doesn't last the whole thing goes in the trash and I buy something else. I run this every day maybe the batteries won't take that I don't know. But if you're going to run it every day buy something else. This didn't last long enough at all. I wanted to wait a while to be sure I had a good sampling and could post a fair and useful review. It's been 90 days now. We have two large (bigger than standard) labradoodle puppies. 85 and 50 pounds and they're 1st generation so they shed a lot. They also, being puppies, have tore the yard up so it is basically a mud pit and they wrestle, run, and fight constantly. They put a lot of dirt and hair on the floors and in the air. We run "Rosie" every day. Yes my wife named it. It does an amazing job on our hardwood floors and throw rugs. It gets all the hair and an incredible amount of dust and dirt. What I mean by that is we can run our Dyson or the Shark Pet vacuum and then run Rosie and the chamber will be full of dust and dirt when she's done. It's almost disconcerting to know our very expensive upright vacuums leave so much behind. It also has the unadvertised ability to buff our hardwood floors. They shine when she's done and the beater brush is showing no signs of damaging the finish on our floors. I would disagree with some of the reviews and even the manufacturers assertion that it doesn't work well on dark floors. Our hardwood floors are a dark reddish brown. The device works great on them and as I said when it's finished they shine. We have agreed we will never be without one and love this device. It does everything it has been advertised to do and more. Also it is set to automatic power and runs longer than the advertised time on a full charge. We get about 2 hours and 15 minutes. We've put down an additional 6 throw rugs for the rainy snow season in the path where the dogs run when they come in and the time has dropped to around 90 to 100 minutes. Still long enough to cover everything well and more than once. It does keep going until it needs a charge it doesn't just run and go back to the dock. I've noticed in the open areas like our living room it might hit that 2 or even 3 times. The floors are like glass after that. Now for the negatives, and these are not deal breakers I'm just being fair. The dirt and dust I referred to is new to us. we recently moved from Illinois to Ohio. In Illinois the dirt is black. Here it is red or a very light brown. The vacuum gets externally dirty. It gets covered with dust/dirt and does not look good. The device is black and the dust is light colored and is readily apparent. I don't want to put it away all the time or for company so thats a problem for me and more cleaning which is not advertised so I'm mentioning it. Secondly it needs to be emptied every use or every other use. They are all like that except some of the super expensive robot vacuums so I wouldn't mention it except for my third negative. It is hard to clean from a mess standpoint. Not so much with the pet hair but with the dust. When you dump it the dust goes everywhere. Unless you have an empty trash can so you can get it way down inside when you're done the garbage can lid and sometimes the floor around the garbage can is clearly dusty from emptying the vacuum. The filters need to be removed at least every other running and they are also a big dusty mess. I also don't believe they will last as long as advertised. I have an air compressor in the garage and a hand held electric air compressor and use those to clean the filter. The foam piece I rinse in the sink. I don't think that someone without access to those tools is going to get the life out of the filters thats advertised. The device comes with a set of replacement filters and the rotating brushes. Not the beater bush though. Our unit is 3 months old. I had to replace the filters at about 40 days and tried to make them last a little longer this time but it hasn't worked out. The outside of the device is filthy. I believe this is due to the filters. The brushes have lasted longer than the suggested replacement time. They are 90 days old and still look like new. Last and has been a rare negative. The device will get stuck under things. Once I learned what the obstacles were in our home it was easy to fix. Some areas I blocked with rolled up moving blankets. I pull the chairs out from under the kitchen table to allow room for it to maneuver. If I don't it gets under there and spends way too much time cleaning and trying to get out. I'd rather it spend less time under there so it can do the whole cleaning area and have power left to do it again. I had the problem spots corrected and figured out within the first 30 days. I've read some units have a tape or something the vacuum will sense and avoid. I wish this unit had that but then again at this price point that is probably an unfair expectation. So those are the pro's and con's we've encountered. The con's are all minor irritants and not a reason not to buy the device as all of these devices are prone to these issues except one or two of the very very expensive units. To repeat what I said earlier this device has worked out so well we have decided that we will never be without one and that when the time comes to replace her we will not feel bad about spending the money for a high dollar unit as it is worth it. Time is worth more to us than money and this thing saves us a great deal of time. It does great job, has done no damage to anything, and if it weren't for the clean up issues would be a five star review. I hope this helps someone make an informed decision and I hope you buy one. It's an amazing little machine, stands up to all the reviews, and truly is the best bang for your buck in robot vacuums.
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Reviewed in the United States on January 1, 2020
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Verified Purchase
L. S. Brodsky
Carnegie, US
★★★★★ 5
Absolutely amazing! Working flawlessly for over a month, so far.
Color: White
I am very pleased with the performance so far. The strengths are the ease of setup, the accuracy of its mapping and carpet/floor recognition, the quality of its cleaning and mopping, and the entertainment of just watching. There are weaknesses. The documentation is sparse and pretty useless and tech support has been ghosting me..no responses. So hunt and peck with the App, mostly. Hard to really customize by trial and error. While it vacuums very well, it does not empty as well, really requiring the owner to manually empty the dust bin. No big deal. Maintenance recommendations are hidden on the website and I suspect it is advisable to do some maintenance after every use. The strengths win, however.
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Reviewed in the United States on May 23, 2026
T
Verified Purchase
TLC
Louisville, US
★★★★★ 5
User friendly, Pet Hair Approved, Quite Powerful Robot Vacuum
Color: White
We prviously had an Eureka E10 vacuum and mop robot for 4 years. We had no idea what we were missing until we purchased this Narwal Freo X10 Pro. It maps very fast. It is extremely quite. The vacuum then mop with a refreshed mop head solution is much better than dragging around a robot mop pad with no way to clean it without removing and washing it. We have 3 Australian Sheppards that shed alot. This was the number one concern, whereas the prvious unit needed daily attention. Not a single hair tangle in the floating rotating brush of this unique Narwal Freo X10 Pro Robot vacuum. 4 months of no robot management is wonderful. The application was easy to use with a ton of customizable options. The AI option to recognize various floor types and throw rugs ensures a complete clean and quick simple setup. Lastly the price vs product was very reasonable. Great product! After spending many months researching, we are glad we made this investment.
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Reviewed in the United States on December 5, 2025

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