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Diesis Akis - floorstanding loudspeakers

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[Italian version]

Product: Diesis Akis, floorstanding 2-way loudspeakers
Manufacturer: Diesis - Italy
Approx. price: 1,744 $/Euro (pair)
Reviewer: Lucio Cadeddu

[Diesis Akis]
Diesis Akis

Diesis is a new Italian Company, located near Perugia, that specializes in loudspeakers, floorstanders, to be more precise. The Akis is the smallest model of their line, which consists of 3 models and some speaker for Home Theater purpose.
Roberto Spera is the name of guy behind Diesis. He has very personal and strong opinions on how a loudspeaker should sound and so his approach to loudspeaker design is quite uncommon and not exactly "mainstream".

My first contact with Diesis stuff was an ad I saw on an Italian HiFi magazine, that ad immediately reminded me the good 'ol Seventies: a loudspeaker, together with a nice blonde girl (the ad can be seen on the Diesis website) and a comment that, roughly translated, read as "They are Neuter (the name of the loudspeaker)...though she is NOT".
It made me think at some glorious '70s loudspeaker reinvented. And I was wrong :-)
The Diesis stuff is pretty modern, both on the sound (more on this later) and manufacturing. For example, their speakers are fully CE compliant, which means they make use of Speakon Neutrik connectors (though a pair of traditional posts is hidden behind two wood caps) and the drivers are protected by a rigid front grid, so that children can't damage them.

Technically, the Akis is a "tower", tall and slim, pretty heavy and fairly finished in natural Italian walnut. It is a two-way design that makes use of a Focal woofer and a tweeter that seems a Scanspeak. I say "it seems" because Diesis hasn't allowed me to "open" the loudspeaker, considering the drivers had been literally glued to the cabinet.

The bass reflex loading makes use of a 3-chambers system and the crossover network is of the uncommon "series" type. No matter how hard I tried to know more about the Akis, Roberto Spera has refused to give me further details, since he was/is afraid of competitors copying his ideas. More on this later (manufacturer's comment).
I can just report the claimed specs:

The Akis comes into a BULKY (can you spell B-U-L-K-Y ?) package that contains the two speakers packed individually and a MASSIVE wood box which weighs something like 90 kgs in total (that's almost 200 lbs to move, my friends). OK, I'm pretty fit but moving a 200 lbs wood box upstairs hasn't been an easy task, believe me! Who said reviewing HiFi stuff is relaxing??? I definitely need some more gym :-) For sure, the Diesis guys take care of their stuff!!!
The Akis measures are: 103 (H) x 21.5 (W) x 28 (D) cm and one speaker weighs in 22 kgs (45 lbs).

I've listened to the Akis over a long period (3 months) into my main reference room and system.

The proof is in the pudding

Roberto Spera of Diesis claims a large number of commercial loudspeakers isn't truly "HiFi" because the frequency response (in room) is monotonically and fastly decreasing at the highs. He claims his speakers have a FLAT frequency response. As you may know, we don't measure the HiFi gear we test, just throw an ear at 'em. So what you're about to read are the listening impressions of yours truly, together with the ones of a panel of 3 different audiophiles who have had the chance to listen to these spekaers while they were into my system.
Let me remind, once again, that my listening room is 30 sqm large, it sounds pretty neutral and it has been acoustically treated to have a clever mix of absorption/reflection features. Also, the gear I use for tests is definitely much more expensive than the speakers under test.

The Diesis Akis has a tonal balance which ABSOLUTELY favours the mid-high range so that, with ANY musical program, it is the mid-high range that dominates the listening experience. Don't get me wrong, these speakers don't sound harsh, thanks to the high quality of the drivers used, the sound they produce is always clean and detailed with very low distortion levels. But! cymbals, female voices, triangles and similar instruments are definitely ABOVE the rest of the musical program.
Puzzled by this strange tonal balance I've started to try everything I could: positioning the speakers in different and weird ways, changing power amps etc. I've even tried to hook up the muscular Krell KAV 300i, an integrated amp that has a stunningly powerful bass range for the price. No way to go, dudes, the Diesis Akis were there, no matter how hard I tried, with their unusual tonal balance.
The only thing that worked has been an extreme amount of "toe in" of the speakers together with a "tilt upwards" of the front baffle (the Akis comes with 4 adjustable feet).

So, after all's been said and done, the tonal balance is as described: mids and highs above the rest, great detail and a "shy" bass range, unexpected from a Focal 17 cm woofer loaded into a large volume reflex enclosure.
Let me add that the Akis has, in my opinion, a pretty strong 5-7 kHz range since ANY of my CDs sounded like they were old compact cassettes without Dolby NR. The "tape hiss" of the master tape, no matter how good was the recording, was CLEARLY audible. With the "Cantate Domino" (Proprius Recording) the amount of tape hiss was simply unbearable for my ears.
If you want this kind of "introspective" attitude :-) the Akis is the loudspeaker for you, provided you can live with a bass range which can't be defined "punchy" or "powerful". It does reproduce low notes, but lacks energy.


Scary fast. What else can I say? Attacks, especially in the mid range, are lightning fast, though I admit decays are much slower, especially in the bass range.
To get the whole picture, the Akis does sound fast, though not "explosive". In other words, the "macro" dynamics performance is just fair, though the Italian speaker excells in the "micro" dynamics department.
No harsh compression can be detected, even at loud listening levels, though the tonal balance of the speakers invites you to turn down the volume oftentimes. Yes, the tonal balance gets more and more "highs-oriented" the louder the listening level.
Na, na, not good for loud listening levels maniacs. Also, please consider that at very low listening levels the woofer simply evaporates and the tonal balance shifts towards an overbright and thin sound.
So, both very high and very low listening levels aren't welcomed.

3D soundstage

Wow, you can easily guess this one by yourself. With such a tonal balance and tweeter "leading" attitude, you can take as granted an over-detailed soundstage with serious "pin point" imaging. The scene is quite large and so rich of details you wouldn't believe you are listening to a sub-2,000 $ 'speaker. Also, the 3D stage is completely apart from the speakers, even if you don't listen in the usual centrally placed position.
If you prefer a more "solid", plastic and dark 3D scene, you'd better search elsewhere, though.


Nothing much to say about craftsmanship, considering the price. Just let me remark the front baffle isn't perfectly aligned with the cabinet (an misplacing of +/- 1 mm was clearly visible) and that the Diesis logo could have been something better than a small paper sticker on the tweeter baffle.
Also, while the rest of the cabinet has a good Italian walnut finish, the front baffle is black varnished is a way that I'd prefer NOT to see in a 1,750 $ loudspeaker.

As for the sound, I think I've already explained it all. If Diesis wanted to make a loudspeaker with an ATTITUDE, the target has been perfectly reached. Considering the vast majority of "common" listening rooms favours the mid-high frequencies, this approach can cause, in my humble opinion, more than one problem to the customer.
Moreover, please consider I've tested the Akis with some of the best power amps available in the market, all with a punchy and extremely energetic bass range. The normal customer of a 1,700 $ loudspeaker will probably use just a "common" integrated amp that, if even of the "audiophile" kind, can't rival the performance of hi-end power amps.
So I guess that, in "man of the street" operating conditions (bright sounding room and system) the tonal balance of the Akis can easily become "too much of a good thing".

Some advice

As for positioning, I suggest to keep the Akis far from the rear wall, otherwise the mid-high range can become harsh and distorted. Do not try to improve its bass range positioning the speaker near the rear wall because things will just get worse: the bass doesn't become more powerful as expected and the mid-high range starts to sound harsh.
If you want to "tame" the tweeter a little bit, apply an extreme amount of "toe-in", that is, angle the speakers at 45 degrees or more towards the center of the listening triangle.
As for sparring partners, avoid bright sounding stuff like the plague, perhaps a warm old-fashioned classic-sounding tube amp can be a solution, even considering the electric "load" offered by the Akis seems to be an easy one.


If you like a bright sound, with plenty of detail into a lively crystal-clear soundstage, the Akis may be well worth considering. I've already expressed my "doubts" with respect to this approach but I'm impressed by the pride of this "new kid in the block" who doesn't mimick or copy what others have done before him. For a beginner, definitely a "plus".

A heart-felt thank you to Diesis and Roberto Spera for having sent us these speakers for reviewing.

© Copyright 2000 Lucio Cadeddu - http://www.tnt-audio.com

Manufacturer's comment

We want to make some remark so that readers can better understand our philosophy.
We firmly believe that many commercial loudspeakers DO have a strongly decreasing frequency response in the 1-8 kHz zone. This causes a "shut-in" sound that doesn't allow to reveal all the details in the records. Many of the harmonic and spatial informations simply get lost.
It is hard to tell and understand why the Akis has produced the sensation of an unbalanced "tonal balance" when listened by Dr. Cadeddu. He says his listening room is "neutral" sounding. One thing is sure: the Akis generate an utterly transparent and open sound, better than many 'speakers that are even more expensive. Not only, their sound is harmonically rich (though the review doesn't talk about this attitude) especially in the mid-high range, where the human ear is mostly sensitive.
This result, which is very positive for us, has been obtained with a serious design and not with an unbalanced frequency response, as Dr. Cadeddu says (without proving this with any graphic).
One can say that even Diesis doesn't publish any frequency response graphs of its loudspeakers, but we think it should be the review to produce such grahs, not the Manufacturer.
Also, it seems Mr. Cadeddu knows how the Focal woofer should perform, and it seems he knows this better that we do. We can guarantee we have performed an extensive research on the loading of that driver, just to get a perfect balance between "speed" and frequency response in the bass. Moreover, the Akis makes use of an uncommon "series" crossover network without any impedance compensation. This, as far as we know, has NEVER been done in a commercial loudspeaker, a novelty that can be quite interesting for customers.
We are a small Company with limited funds, so our innovative designs are our main resource and for this reason we refuse to give further details on our loudspeakers. We are sure you readers can understand our position.
Finally, something about our prices. Our loudspeakers aren't sold-direct so the final price should take into account the various "steps" of the commercial chain.
I'd like to thank Dr. Cadeddu for the time he has spent listening to our loudspeakers.
Spera Roberto for DIESIS.

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