SEISMION REACTIO 2 REVIEW
Seismion Reactio 2 is a high-end and high-technology product, aimed at those looking to provide their HiFi gear with the ultimate isolation from external factors. Janine Elliot has a play with it and gives us her thoughts.
I have seen some unusual and amazing things over the years, like Pioneer “Pure Malt” loudspeakers made from old Whisky barrels, remote controls that you have to wind them up to power them (you’ll probably use less energy just getting up off your settee), trouser presses to flatten your warped records, recently a record weight that turns into a disco light (ideal for when you play Beethoven), and never forget the aluminium foil and furniture polish that Peter Belt told us would improve our HiFi. What I was sent this time is equally unusual and actually works really well, though it does cost an arm and a leg, and was in fact never actually designed for HiFi in the first place.
The Seismion Reactio 2 is an active vibration suppressor that you place your turntable, valve amplifier, or whatever suffers through vibration on. Forget springs, spikes or rubber feet. This does things differently. This German manufacturer is dedicated to the science of advanced mechatronic systems and vibration technology, a company set up to create anti-vibration products for industrial use in Metrology (Metrology is the scientific study of measurement), where the slightest vibration will affect the readings or even the manufacturing of a product.
Dr Marcus Neubauer of Seismion studied mechanical engineering in Hanover for his PhD, concentrating on vibration and dynamics. After this he continued his work in vibration damping and absorbing mechanics. He particularly concentrated on the use of piezoelectrics, and after a time researching in China, returned home and, with fellow vibration isolation guru Sebastian Mojrzisch, set up Seismion.
Sebastian previously worked at Volkswagen as a project manager. Their company not only develops and manufactures active vibration isolators for industry, but they also offer a service of analysing and developing solutions for a customer’s problem using modal analysis or element calculation. It was only after a few audiophiles started using their equipment to cancel vibrations in their HiFi system that the company delved into audio solutions. At £10,250 for their Reactio 2, it is not a cheap solution, but the fact that it can support up to 65kg and the inside of its unassuming grey/black sandwich box is crammed with mechanics and technology, then you realise it is actually worth its weight in sound. Their £12,750 Reactio 2XL can support a massive 150kg, their Atlas can support 1 ton, and if you ask them nicely, they will make it even stronger; they have even made a 10-ton isolating device for one customer! It is worth noting that the turntable manufacturer Thorens brought out the €220,000 Reference turntable to mark their 140th anniversary in 2023, which also has piezoelectric technology built in and made in collaboration with Siesmion.
So, what is hidden inside? Well, the top black platform (isolated top-plate) is basically supported by motors that ensure that the unit is always kept balanced perfectly. Extremely sensitive piezoelectric sensors detect any external vibration, and the internal circuitry then tells the motors how to respond to stop the vibration. Vibrations are measured by sensors in all 6 degrees of freedom and active control forces are applied by contactless actuation.
A typical use for the Seismion would be a turntable, or perhaps a valve amplifier (valves are easily affected by vibration. The internal components, when vibrating, can interfere with the electron paths and the magnetic fields, making them effectively act as a tiny microphone to convert mechanical energy into an electrical signal!) But you could always buy two and place your loudspeakers on each one! The 150kg load-bearing Reactio 2XL could perhaps even be used to support your complete audio rack. As well as the high level of precision automatic levelling, it also has a locking function so that you can compare the unit with or without the isolation, to check if it is working.
SPRINGS, RUBBER AND SIESMION
Having been great friends with the late, great Max Townshend, I have learned a lot about isolation, especially air springs. My HiFi rack is a Townshend Seismic Sink. Seismion, however, claims their active system is far superior to air springs, especially in the low-frequency range up to 10 Hz. Their marketing blurb suggests their technology reduces vibrations by a factor of 7 at 5Hz, and at 2.5Hz it has 37-times higher isolation than air spring isolators can achieve! The transient response (the time it takes to stop vibrating) is also significantly better. While air spring systems take several seconds to get to their resting position, the Seismion active isolators can bring the system to rest within fractions of a second, and can even operate at below 1Hz.
BUILD QUALITY AND FEATURES OF THE SEISMION REACTIO 2
The unit might look like an enlarged Liquorice Allsort, but its bland appearance and black/grey colours are perfectly correct in my opinion, as you don’t want it to overbear the HiFi. However, you can request your own customised colours and finishes, should you want to be a bit more adventurous. The unit (40 x 50 cm) is big enough to cater for most audio components, though my first guinea pig for this review, my aged Hydraulic Reference turntable, was able to just squeeze on (it is very deep).
The Reactio 2 claims a 10dB loss at 1Hz, rising to 20dB at 5Hz. This is the frequency where most disturbances are usually felt. These sensors are absolutely silent, so you won’t hear anything when the unit is in operation, and their operation is accurate to a repeatability of 25µm, which is an incredibly low number, and much better than a spirit level! The 92mm tall unit sits on four very thin rectangular rubber bases at each corner. When I first unpacked the unit, I thought these were incredibly insufficient, until I realised the whole point of the box; it just wouldn’t work accurately if it had big spongy rubber feet! The build quality is excellent, and the unit just has a button at the front with a built-in LED to indicate different stages of set-up and use.
SETTING UP THE LIGHT SHOW
Once the unit is first positioned for use, it is necessary for it to self-level. The LED will initially be RED, and with a short press or long press, you can change how it is being/not being used. With a short press, the active isolation is switched on and it levels itself (it might make an audible noise when it does this). Whilst levelling, its status LED blinks RED/GREEN, and then turns GREEN when all is OK. If nothing has changed the next time you switch it on (ie, you haven’t swapped the HiFi), then it will miss out this adjustment stage. Balancing is done by contactless voice-coil actuators, so no sound is emitted. You can turn off with a short press of the button, and it then indicates RED. You can lock the top plate with a long press of the button, so that even “passive” suspension isn’t operable; I used this so that I could compare the suspension vs no suspension, and also when changing settings on the SME tonearm (as the weight from your hands would affect the Seismion readings). This is also needed if you are transporting the unit so that it doesn’t get damaged. The LED lights yellow whilst it is levelling, and then blinks RED. To activate “active” isolation again, all you need to do is a short press of the button. The instruction booklet supplied is very good, so if you were to buy the Reactio 2, then I would highly suggest careful reading before you use the machine.
THE RESULTS OF USING THE SEISMION
I was very impressed with the technology, but would that £10,250 be a worthy outlay to improve my listening experience? A turntable was the obvious first stop in testing this possibility. I would loved to have put on my Pre-Audio Tangential turntable and air-pump on the Seismion, but that wasn’t possible on several fronts, not least my back (it’s very heavy!). With the air pump blowing at around 20Hz it would have been interesting to see if the Reactio 2 could react. As the Seismion wasn’t initially designed for HiFi use, I decided to use a turntable that also wasn’t initially designed for use as HiFi; the Transcriptors Hydraulic Reference was originally built just as a prop in the film “A Clockwork Orange”. I used my Michell Hydraulic Reference as it doesn’t have spring or rubber suspension, and also because the SME3s arm on it is very high-compliance, meaning tracking at 1g would pick up the slightest vibration. Cartridges are particularly affected by low-frequency vibrations – as those who use Townshend damping-troughs (developed at Cranfield Institute of Technology) will know only too well. Also, I live very close to a railway line, so the 22-wagon-long Class 66 locos supplying ballast or oil up north can easily interfere with my vinyl playing.
Tangerine Dream’s 1975 ‘Rubycon’ was the first spinner. It is basically a two-movement album, side 1 starting with lots of low-frequency gongs and synth notes plus “wishy-washy” ambient effects. This usually can sound rather confused and boring, but as soon as I turned on the Seismion, that bass almost instantly became clearer and even the music “widened” as each line of notes and chords became more precise across the sound-stage. With Mellotron, VCS 3 and Moog synthesisers plus Elka organ it all might sound dated, but this modern balancing tech kept the music up to beat. The repeated D minor “Vangelis” bass phrase was clearer and more focused, and as this long section developed musically, the depth and detail in the soundstage also grew. Turning the Seismion off ,and it all seemed to die.
I often use Bach’s BWV565 organ Toccata and Fugue (Helmut Walcha) to test out bass and control in those lower frequencies, and here the Hydraulic Reference suddenly sounded like a top-end 21st-century icon. The organ was as clear as I have ever heard it, and the Pastorale BWV590, which followed, opens up clear organ playing even further. I’m not saying you can put any rubbish on the Reactio 2 and it will magically become a million dollars, but many of the Reference’s shortcomings were rectified here; the HR really shouldn’t work! I guess a really well-isolated turntable, such as the AVID Dark Iron I recently reviewed, would be a little less effective, and therefore I would have liked to have still had my home-built Garrard 301, which has absolutely no suspension, to test the Seismion.
With the recent sad news of the Supertramp keyboardist (and singer) Rick Davies’s death from cancer in September 2025, one of my 1970s favourites, ‘Breakfast in America’ would need to be next on the turntable. This has lots of mid-frequency information in it; grand piano, gorgeous, sweet vocals from Roger Hodgson, who left the group in 1983, saxophone from John Helliwell, and string synths. It can often sound a bit claustrophobic, but the Seismion seemed to unfold it into a larger piece of musical expression, allowing me to get more involved in what the great man was doing before he took the piano keys to the next life.
I couldn’t put the Reactio 2 back into the cardboard carton before trying it on my valve power amps. As mentioned earlier, valves are very microphonous (have I just invented a new word?), meaning they are influenced by vibrations around them (something that has always confused me, in that the best microphones have valve amplifiers in them, eg Neumann U47). I put tube damping rings on all my valves to stop them being affected by vibrations, which is a lot cheaper than the Seismion, but could the sound be improved still further? Although the effect wasn’t as profound as with the turntable, but the effect was still there. Perhaps it was stopping the internal mesh anode from moving. Music certainly seemed more purposeful and controlled, especially in the bass frequencies, reducing distortion and noise by a degree.
QUIBBLES
It’s hard to find a fault in an original product such as the Seismion, especially as its ability to suppress vibration was greater than air-springs. Its shape and colours do make it a little bland, perhaps. If it had an LED screen showing exactly what it is counteracting (such as is on the Thorens Reference turntable) then that might persuade more people as to its merits.
CONCLUSION
£11k for damping might sound a lot of money, but especially in areas where there is a lot of external vibration, such as near an airport, motorway, railway, or if you have wooden flooring and noisy neighbours below you, then I can see a very good reason to invest. The fact that even with my concrete floors and no trains passing I could hear improvement in my turntable and amplifier, then this should certainly be on your shopping list for improving your HiFi.
AT A GLANCE
Build Quality:
Solid and good construction and internal technologies
Sound Quality:
Improvements in bass tightness and mid frequency soundstaging
Value For Money:
£10,250 is certainly a good investment in further improving your audio system
We Loved:
Control of bass
Impressive improvements in soundstage and timing
Greater detail in mid frequencies; vocals, strings, piano, etc
We Didn’t Love So Much:
Just wish it was cheaper!
Elevator Pitch Review: We are often told to improve our HiFi with gadgetry such as special fuses, cable supports, and perhaps even special aluminium foil and furniture polish. Seismic stands were made famous by the great Max Townshend, but they cannot offer the same speed of stabilisation as an active system. Seismion has been designing active balancing devices to be used in industries where the slightest vibration or movement might hinder a reading or ruin a construction, but when audiophiles in China found that it also improved their HiFi, Seismion decided to make a move into this market as well. With particular benefits of using the device for turntables and valve amplifiers, I thought I should give it a listen and see if I could be swayed into investing in the £10,250 Reactio 2.
Price:
£10,250 Reactio 2
£12,750 Reactio 2XL
Janine Elliot
SUPPLIED SPECIFICATIONS
Dimensions: 500 x 400 x 90mm
Weight: 14.5 kg
Payload range: 0–65 kg
Automatic levelling: 25 µm repeatability
Maximum power consumption 25W (typically 4W)
Operating temperature 15-25 degrees C
DC plug with a 2.1 mm inner diameter pin
Reactio 2 XL as above except:
Dimensions: 600 x 500 mm
Payload range: 0–150 kg
