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SPEAKERS • floorstanding


Producent: GRADIENT LABS Ltd.
Price (when reviewed): PLN 39,990/pair

Contact: Gradient Labs Ltd.
Kisällintie 8
FI-06150 Porvoo | FINLAND



Provided for test by: AUDIO ATELIER


images „High Fidelity”

No 224

January 1, 2023

The GRADIENT company was founded in Finland in1984 by Jorma Salmi (1948-2018). The aim was to produce speakers that would behave well primarily in the listening room, not just in an anechoic chamber. Since 2010, the company has been managed by Jorma's son, ATTE SALMI.

NYONE WHO HAS SEEN the R-5 Revolution speakers that we are testing has their own opinion on their looks. Some associate them with the R2-D2 robot from Star Wars, to others they resemble “the eye of Sauron”, while yet other people go back to the times of the Polish People’s Republic and recall “Frania” – a semi-automatic washing machine. Nevertheless, as it seems to me, the tested designs resemble nothing but themselves and the 1.4 model that preceded them, and our reactions reveal more about ourselves rather than the speakers. They show that audiophiles are an incredibly conservative group of people, even though we see ourselves as progressive and open to novelty. But it’s not like that.

From 1.3 to R-5

THE R-5 REVOLUTION SPEAKERS have a classic three-way four-driver design. Their distinguishing feature is the application of these speakers. The unusual shapes of the R-5 hide solutions that have been developed by Gradient for many, many years. We told the story of speakers allowing for possibly omni-directional sound propagation in our test of the company's model 1.4. The speakers tested this time are its development version (more → HERE).

In 1982, during the 71st AES convention in Montreux, JORMA SALMI, later founder of Gradient, and ANDERS WECKSTRÖM, who was hired by him, presented a paper entitled Listening room influence on loudspeaker sound quality and ways of minimizing it. In the paper, they pointed out that almost every properly designed speaker behaves surprisingly well in an anechoic chamber, and the differences between them begin to play a role only in classic listening rooms.

⸜ Gradient 1.3 speakers from the year 1989

Two years later, Mr. Salmi founded his own company, Gradient, to which he co-opted two associates, Jouko Alanko and Mikko Paloranta. The aim was to produce speakers that would realize the basic idea: work as well as possible in the listening room, not just in an anechoic chamber. In 1989, the company proposed a model from which its history really starts: the 1.3; it wasn’t THE first speaker by Gradient, as in 1984, Gradient launched a first speakers 1.0 and 2.0 later 1.1, 1.2, 2.1, 2.2, but most important. An oval-shaped bass driver was mounted diagonally on the bass base, and a tweeter array consisting of four tweeters was mounted above it. These ideas later led to the creation of the Helsinki 1.5 model. Their development was the 1.4 model, which featured a coaxial system supported by a bass driver. The tested R-5 (R = Revolution) are the company's next step towards becoming independent of room acoustic conditions.

The R-5

THE R-5 SPEAKERS FEATURE a three-way, four-speaker design. The woofer is mounted in the lower module, and the coaxial driver in the upper module. Both operate in open (!) enclosures. There are two technologies in their design that particularly draw our attention. One of them is connected with the open enclosure, while the other one – with the coaxial driver.

| The coaxial. A story in a few words.

⸜ The coaxial driver in Gradient R-5 speakers

IN THE PARADIGMATE FRAMEWORK in which a coil moves in the magnetic field of a permanent magnet (formerly an electromagnet), and then the coil moves a diaphragm, designers tried to find the best possible solution to problems such as limited frequency response, low efficiency, non-linearity, high distortion, etc. In 1926, Herman J. Fanger obtained a patent on his idea that we now call a “coaxial driver”. His description pointed out that it is a system of two speakers, of which the tweeter (with its own diaphragm and a short horn) can be placed in front of the diaphragm of the larger speaker or in its center.

The first commercial realization of this idea was the two-way Altec Lansing Uplex Coaxial driver, model 604, from 1943. This was a solution also used by the Tannoy company, in the Dual Concentric driver. There, the tweeter was on the axis of the woofer, but the acoustic centers of the two system drivers were not in the same plane (one diaphragm was closer to the listener and the other one further away). In modern times, this idea is also being developed by the company FYNE AUDIO (PL).

⸜ A coaxial speaker in the Fyne Audio F500SP speakers

Thiel, CABASSE and Piega companies also presented their versions of coaxial drivers. An interesting solution was also proposed by the German company MUSIKELECTRONICS GIETHAIN.

The best-known coaxial system, however, is the Uni-Q, developed in the late 1980s at KEF. This system assumes not only the coaxiality of the tweeter dome and woofer cone, but also the compatibility of their acoustic centers. Over the years, this system has been refined and is still used in the company's loudspeakers today, and its versions can be found in TAD and Pioneer loudspeakers (review → HERE). The Polish company ANTIMATTER proposed its variation in 2017.

THE GRADIENT COMPANY ALSO USES OTHER drivers, developed by the Norwegian company SEAS. The first coaxial driver was used by Gradient in 1993, in the Revolution model. But it was the 1999 Prelude model that brought it into the homes of less affluent music lovers. This type of system, characterized by phase alignment, became the favorite choice of this Finnish manufacturer. So, on the wave of Prelude's popularity, other small monitors were created: the Lauri, Laura and Five models (test → HERE).

The idea behind these speakers was so compelling that in 2002 Gradient designed loudspeakers for Mr. Kiuchi, owner of the Combak Corporation, which, having been fine-tuned in Japan, with a different enclosure and an addition of a few components, were given the name Bravo! (test → HERE [PL]). All of them used a system from SEAS, and the 1.4 model, for the first time, used a coaxial system modified for Gradient in Finland. The driver used in the R-5 is the latest version of the solution, and the company calls it “one point source”.

The coaxial system consists of two drivers here. The low mids and mids are reproduced by a 176 mm speaker with a diaphragm of lacquer-coated paper. An aluminum-magnesium alloy dome with a diameter of ø 25 mm is placed in the middle. The division between the two is set at 2.5 kHz. In its fundamentals, the system resembles the one used in the 1.4 model. The drivers are housed in a spherical enclosure, which is a kind of a baffle open at the back.

There are also two 300mm woofers in the baffle. They process a bandwidth of up to 200 Hz, and their wave has a dipol shape, similarly to electrostatic speakers. As a result, the speakers exhibit almost zero bass radiation on the sides. In the manual we have typical and less typical examples of using this feature. Diagrams show both classic rooms and irregularly shaped ones. The company's materials clearly state that:

When compared to the conventional closed box or bass reflex systems you will get the same sound pressure level at only one third of acoustic energy. Thus the room colouring effects are much less annoying and your neighbour will hear less of your bass lines.

Gradient R-5 – the new revolution, →, accessed: 15.11.2022.

The speakers are made of natural materials, such as MDF board, plywood and fireboard. The characteristic oval enclosure is made of MDF and steel, and a fabric stretched over the frame. The coaxial driver sphere is put on top. A cutout in the top wall is used for this purpose – the system is connected via an XLR plug.

The speaker cable is also connected in an unusual way. Classically, this is done via speaker terminals - not a very convenient way, but taken for granted in our industry. Since in the R-5 signal is fed from below, speaker terminals would be impractical. Instead of them, we have professional angled Neutrik speakON connectors. As part of the set, we also get a Cordial speaker cable.


⸜ THE WAY WE LISTENED Similarly to the 1.4 model, the R-5 is also very easy to set up. A lot of useful information can be found in their user manual. It points out that they are best spaced at a distance corresponding to their distance from the listener, that is, in the plane of an equilateral triangle.

The isolated mid-high driver module, the "sphere", makes it possible to introduce significant changes in the loudspeaker geometry. We can position it any way we want, either on the vertical or horizontal axis. In fact, the idea is to have the coaxial system pointed exactly at the listening position. In the company materials we read that the dome tweeter uses the midrange driver's diaphragm in the role of a horn to improve its directivity. The system is thus supposed to feature a cardioid waveform. The company says that the midrange is attenuated in the rear direction by 20 dB.

The woofer module, on the other hand, can be set up in several different ways: parallel to each other, at an angle, or even turned sideways to the rear wall and the listener. In this way, we take advantage of the figure-eight radiation characteristics of the bass. From the sides of the speakers the pressure is the lowest, so they can be "tuned" in such a way that the bass is stirred up as little as possible.

⸜ Albums used in the test | a selection

⸜ CHARLIE HADEN & KENNY BARRON, Night and The City, Verve Records 539 961-2, Compact Disc (1998).
⸜ CHARLIE HADEN & PAT METHENY, Beyond The Missouri Sky (Short Stories), Verve Records 5371302, UHQCD (1997/2022).
⸜ ELLA FITZGERALD, Songs In a Mellow Mood, Decca/Universal Classics & Jazz UCCU-6068, „Universal Jazz The Best ⸜ No. 68”, SHM-CD (1954/2011).
⸜ EURYTHMICS, Sweet Dreams (Are Made Of This), RCA Records ND71471, CD (1983/1987).
⸜ TOMASZ PAUSZEK, 20 Years Live, Audio Anatomy [AA-011-19-LP], 2 x Master CD-R [niewydana wersja CD] (2017).
⸜ LED ZEPPELIN, Led Zeppelin IV, Atlantic/Warner Music 8122796431, „Super Deluxe Box Set”, 2 x CD + 2 x LP (1971/2014).


THE SOUND FEATURE THAT all designers are working on, and which is incredibly difficult to achieve, is coherence. The idea is to make individual driver units interact with each other and make all of them interact with the room in such a way that it is impossible to tell where one stops playing and another begins. With the R-5 we get this right away, this is our starting point.

What's more, it happens almost regardless of where and how we place our speakers. It is obvious that optimizing their placement is advisable, but it is not crucial. What is most important seems to be "implanted" in the speakers themselves, in their design. So, the Gradient speakers will be one of the few speaker designs which let us obtain most of their advantages in acoustically challenging rooms, and in rooms where the speakers cannot stand exactly where we would like them to.

The coherence I'm talking about, by the way, goes deeper than just the temporal alignment of the speakers, giving the impression of a single broadband driver playing. It's something in the structure of sound itself, causing it not to attract our attention, like with the album Night and The City by CHARLIE HADEN and KENNY BARRON. This is one of three titles released in the second half of the 1990s by the Verve label, in which Haden plays duets with jazz greats – apart from Barron, the year before he cooperated with Pat Metheny on the album Beyond The Missouri Sky (Short Stories) (1997) and Jim Hall on the album Charlie Haden/Jim Hall, released much later in 2014.

The sound of Hadden and Barron's album had something of a mystery about it. It was recorded live at The Iridium club in New York. When the applause and shouts of the invited guests are heard in between the songs, with the R-5 we will get the impression as if we were transported to our listening room. I guess that you often read about how a performer "materialized" in front of the reviewer. However, I know from experience that this is usually not quite true. This is because all that is required in most systems is the impression of the performers' "presence", to make it seem that this is really the case, by way of contrast to weaker reproductions.

In Gradient speakers this is given right from the start, and the whole message is built on this. In doing so, the R-5 don't perform any "magic tricks", flips and tumbles. It's not an artifactual space, or at least that's not how we perceive it. The space in front of us is solidly and fully filled with sound. And when a duet is playing, like a piano and double bass, even though we know it's a stereo recording, we don't perceive it as artificial. Applause draws our attention to the width of the stage, but the instruments themselves suggest it by reflections, not by being unrealistically spread out on its sides.

The difference between the over-interpretation of space offered by most speakers and realistic space - as far as recording technology allows - was demonstrated by ELLA FITZGERALD's monophonic album entitled Songs In a Mellow Mood. In this material, recorded over two March days in 1954, the singer's vocal was located in front of Larkin's piano in a large space, but without magnification. This is the thing that distinguishes these designs from other speakers that feature coherent sound.

In terms of color, the R-5 are situated right between “warm” and “transparent”. They have an equalized frequency response, or at least that's how we hear it in the listening room, so you won't find them too "rounded" or "warm" on the one hand, but, it won't be bright sound, either. It seems that the designers were concerned with producing as neutral a color as possible.

In this case, neutral means interesting, as opposed to impersonal, boring, emotionally washed-out designs, often with excellent measurements, but where listening has been forgotten. The Finnish speakers show the "presented world" with commitment, in a dense manner. It's density that stems from high resolution, not from boosting. This is because these are not designs that play low and meaty bass. As a matter of fact, with the recordings I've recalled they sound like large standmount speakers, until you realize that the volume is very large, and the space extends in every direction further than with other speakers. And this is impossible to do without a precise bass base.

In fact, the bass base is preserved really well in the R-5s, especially in the context of their dipole bass. When I played TOMASZ PAUSZEK'S album 20 Years Live from a Master CD-R disc, I obtained tremendous space and midrange that was full of events. The space did not just play out in front of me, but also on the sides and behind me. It was there that sounds generated by the musician, reminiscent of an analog computer from the 1960s, were located. The timbre was extremely smooth, almost silky. The treble had a soft attack, though it was very accurate indeed. The bass, on the other hand, had a clear pulse, but most of all it was selective.

The longer I listened to the Gradient speakers, the better I saw in my mind the system in which I could listen to them. It’s because they do require some assistance from us, at least if we want to play full-blooded saturated sound which I am accustomed to, having listened to Harbeth M40.1 speakers for years. It is no coincidence that the tested speakers played with the Bladelius Ask amplifier (test → HERE) at the Audio Video Show. It's also no coincidence that they meshed so nicely with the Leben CS-600X amplifier (test → HERE).

The point is that these are easy-to-drive speakers that feel best in the company of electronics with dense color. Only then do they go into "higher gear." Although the Soulution 710 power amplifier I used for testing showed perfectly what the speakers really are, it was the Leben amp that really allowed me to enjoy their sound.

When high sounds were heard in the recording Sweet Dreams (Are Made of This) by EURYTHMICS, the Gradient speakers with the Soulution power amp favored them slightly, as compared to the remaining sounds of electronic percussion. As Dave Stuart recalls in his memories Sweet Dreams Are Made of This: A Life In Music, these sounds were recorded by him and Annie Lennox literally hitting bottles placed at the studio. Let me add that this material was recorded on an 8-track tape recorder, using one of the first Movement Systems MCS Percussion Computer machines.


THE GRADIENT R-5 SPEAKERS have a special ability to vanish from the listening room. They do not draw attention to themselves in any way, leaving us alone with the music. They can be set up in pretty much any way, and they will still play optimally. When set precisely, they will disappear.

Although they are quite large, they do not exude bass. The bass is quite low, but above all it is precise and clear. Unlike in many other designs of this type, one does not have the impression that this range is detached from the rest of the band. To tell you the truth, if I didn't know there were woofers in the bases, I might not have known that – up to the point in the recording where it goes lower at the lower end and the full range can be heard.

All this is because the Gradients offer intrinsically complex and refined sound. It's worth helping them out with a selection of electronics if you want to fill out the low mids, but it's not necessary. They themselves sound like one broadband driver, but without the unevenness and coloration heard with most designs of this type. It is a very, very successful design for virtually any music.


THE R-5 BY GRADIENT are three-way floorstanding speakers. Their shape is untypical and it results from many years of research carried out by the manufacturer on sound waves distribution in real listening rooms. Each speaker consists of two modules: a woofer and a mid/high driver. The former has an oval cross-section and tapers slightly towards the top. The latter is a sphere with truncated cones. In one truncation a coaxial speaker is screwed, and in the other one – fiberboard with cut-out holes.

As it appears, the speaker operates in an open enclosure. It is heavily damped with artificial wool, which only works in the higher frequency range, however. The enclosure is called Acoustic Resistance Enclosure by the company, and is designed to nullify standing waves inside the enclosure and prevent sound waves from bending outwards. The upper module is inserted into a circular cutout in the lower one. Unfortunately, there are no lines to get the perfect level, it is done "more or less". In the horizontal plane, you can rotate the module to get the best stereo image. The vertical plane, however, should be fixed, in my opinion.

The lower module features two woofers, each with a 300 mm diameter. They have paper diaphragms with holes cut out by the Gradient company close to the lower suspension. They also work unusually, in an open baffle. What we see as an "enclosure" is just an MDF and steel frame on which the grille is stretched. In fact, the rear is open and the forward-facing driver works in an open enclosure.

The crossover is located in the lower module, and signal is sent to the upper module via a Neutrik XLR socket and plug. Signal is delivered to the speakers themselves not through classic audio speaker terminals, but through a professional speakON plug. This is Neutrik's own development, widely used in professional systems. It is great mechanically and very good electrically. It is also interlocked in the socket. It was once used by Dynaudio, but the audiophile world forced the classic approach on the company. Sometimes we are really stupid…

We also get cables terminated with an angled speakON plug. This is a quite nice Cordial CSL 225 2 x 2.5 mm2 speaker cable. Made of oxygen-free copper on the amplifier side, it has classic gold-plated banana plugs. However, the set comes with spare plugs of this type, so we can convert our own cables, if their design allows us.

The design of these speakers marks an approach different from that of high-tech YG Acoustics or Wilson Audio companies. Here, it's all about a selection of natural materials and years of listening. And it really works out well.

Technical specifications (according to the manufacturer)

Frequency response: 30-20000 Hz (+/-2 dB, high frequency limit above 50 kHz).
Impedance: 6 Ω, minimum 5 Ω
• 2×300 mm long throw woofer
• 176mm pre-coated reed-paper cone midrange, coaxial Al/Mg dome 25mm
Sensitivity: 88 dB/2.83 V/1 m
Recommended amplifier power: 50-250 W
Crossover frequency: 200 Hz, 2500 Hz
Dimensions (W × H × D): 420 × 1040 × 320 mm
Weight: 35 kg/unit


Reference system 2022

1) Loudspeakers: HARBETH M40.1 |REVIEW|
2) Line preamplifier: AYON AUDIO Spheris III Linestage |REVIEW|
3) Super Audio CD Player: AYON AUDIO CD-35 HF Edition No. 01/50 |REVIEW|
4) Stands (loudspeakers): ACOUSTIC REVIVE (custom) |ABOUT|
5) Power amplifier: SOULUTION 710
6) Loudspeaker filter: SPEC REAL-SOUND PROCESSOR RSP-AZ9EX (prototype) |REVIEW|
7) Hi-Fi rack: FINITE ELEMENTE Pagode Edition |ABOUT|


Analog interconnect SACD Player - Line preamplifier: SILTECH Triple Crown (1 m) |ABOUT|
Analog interconnect Line preamplifier - Power amplifier: ACOUSTIC REVIVE RCA-1.0 Absolute-FM (1 m) |REVIEW|
Speaker cable: SILTECH Triple Crown (2.5 m) |ABOUT|

AC Power

Power cable | Mains Power Distribution Block - SACD Player: SILTECH Triple Crown
Power (2 m) |ARTICLE|
Power cable | Mains Power Distribution Block - Line preamplifier - ACOUSTIC REVIVE
Power Reference Triple-C (2 m) |REVIEW|
Power cable | Mains Power Distribution Block - Power amplifier - ACROLINK Mexcel 7N-PC9500 |ARTICLE|
Power cable | Power Receptacle - Mains Power Distribution Block: ACROLINK Mexcel 7N-PC9500 (2 m) |ARTICLE|
Power Receptacle: Acoustic Revive RTP-4eu ULTIMATE |REVIEW|
Anti-vibration platform under Acoustic Revive RTP-4eu ULTIMATE: Asura QUALITY RECOVERY SYSTEM Level 1 |REVIEW|
Power Supply Conditioner: Acoustic Revive RPC-1 |REVIEW|
Power Supply Conditioner: Acoustic Revive RAS-14 Triple-C |REVIEW|
Passive filter EMI/RFI: VERICTUM Block |REVIEW|


Speaker stands: ACOUSTIC REVIVE (custom)
Hi-Fi rack: FINITE ELEMENTE Pagode Edition |ABOUT|
Anti-vibration platforms: ACOUSTIC REVIVE RAF-48H |ARTICLE|

  • HARMONIX TU-666M "BeauTone" MILLION MAESTRO 20th Anniversary Edition |REVIEW|


Phono preamplifier: Phono cartridges: Tonearm (12"): Reed 3P |REVIEW|

Clamp: PATHE WINGS Titanium PW-Ti 770 | Limited Edition

Record mats:


Headphone amplifier: AYON AUDIO HA-3 |REVIEW|

Headphones: Headphone Cables: Forza AudioWorks NOIR HYBRID HPC