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This review first appeared in Issue 7 (6/09) of Inner World Audio where it can be read in its original Finnish version. The writer translated it personally and we feature it here for the benefit of our English-speaking audience. Kari Nevalainen also contributes to 6moons directly and it gives us great pleasure to return the favor and offer samples of his Finnish work to a broader readership - Ed.

Reviewer: Kari Nevalainen
Financial Interests: click here
Analogue Source: La Nouvelle Verdier with Ortofon RMG-309
Cartridges: Ortofon SPUs, Denon DL-103 etc.
Digital Source: Audiomeca Kreature transport, Sentec DiAna DAC
Preamp: Shindo Aurieges, Dynaco PAS (heavily modified)
Power Amp: Shindo Montille, 6V6 custom design, Sony integrated
Speakers: PHY/Fostex based widebander speakers, Altec 904-8
Cables: PHY, Kimber, Belden, Supra plus various mid-fi cables
Power Cords: generic
Accessories: Sound Organisations rack, Gregitek equipment platforms, different isolator pads
Mains treatment: None
Room Size: 4.5 m wide by 5m long by 2.8 m high
Review component retail (with VAT in Finland): € 9600/pr

Making A Virtue Out Of Necessity
One typical illusion nowadays (a wrong interpretation of reality) is that all of us share the same reality. We believe that by internet, satellite television and the like, all essential information on everything is there on the silver platter, to be admired by everyone in each corner of the world; and that outside this reality, nothing else happens of much true significance. This delusion is a kind of blindness. It seems to me due to the unfortunate predominance of the English language. Despite all the fuss about unification and integration, about the earth becoming a global village and so on, there is an almost infinite number of very interesting projects that have existed for a long time but about which hardly anyone knows a thing - and certainly the English-speaking world does not.

That matter once again sprang to mind while reviewing the Esa Credo 4-speaker. Esa began its operations in Pozna, Poland in 1991. Two years from now they will have existed for 20 years but honestly, how many of you were aware of Esa's existence or its products prior to this review? Or prior to the photo of Esa's Credo 4 speaker appearing on this site's 'coming next' gallery? Even I who half actively follows the international supply chain came across Esa by accident while evaluating another speaker. Based on my first impressions of their Credo series speakers back then, it was clear that I wanted a closer examination of their sonic qualities at some point. With the help of local importer Tur-Pex, I chose the Credo 4 as guinea pig. Of all the Credo series speakers, the 4 stands at the very top.

It is a floorstanding 3-way reflex-tuned affair. While glancing through the manufacturer's technical specifications, one figure drew my attention - the weight of 75 kg each. In relation to its 112cm height, Credo's weight index is 1.49 (height divided by weight). Here are a few other index values: Wilson Benesch ACT 2.07, Avalon Indra 2.05, Audio Physics Avanti 2.54, Tannoy TD10 3.16, JMlab Utopia Scala 1.47, Usher Audio CP-8571 1.26, Sonus Faber Stradivari Homage 0.91. Twice as expensive, JMlab has a similar value and only Usher (roughly the same price) and Sonus Faber (three times the price) have a better index, i.e. are heavier in relation to their height. The weight index normalized with the price, Esa's Credo 4 must be one of the most massive speakers on the market and I argue that it can be heard, too. But not directly. Weight is just weight. Everybody who's bothered with speaker cabinets knows that sheer mass alone does not automatically mean good sound. At least the guys at Esa seem to have realized this:

"The cabinet - its type, size, shape, all inner and outer measurements, enforcements, alignment method, attenuation; the electrical system - type of filters, grade of components, assembly method, cabling; finally, the transducers themselves... this is a very complex system of communicating vessels, closely related phenomena, a conglomerate of mechanical, magnetic, electrical, acoustic components. The secret of the ability to construct speaker sets consists in becoming acquainted with parameters of individual system components and relationships between them, as well as in reading their actual meaning."

Every speaker is a complex system with a number of hard to control characteristics and even certain unforeseeable ones. Daydreaming is not forbidden but it won't take a speaker designer very far. Designing a speaker is to know about various limitations, a willingness to make compromises and take the bull by its horns to solve diverse theoretical and practical problems. I will start unraveling the complex job of Credo 4 from its cabinet and then gradually proceed towards Esa's main speaker-design principle: przesun, pochylni, wyrównaj - relocate, tilt, adjust.

When one observes Credo 4 from the side, it's easy to notice that not only is the front baffle tilted but so is the rear baffle - the cabinet widens asymmetrically towards the floor. Why the front baffle leans backwards becomes soon clear but why the rear baffle is not upright has to do with the cabinet's inner structure whereby Esa seeks to minimize the adverse effects of inner standing waves.

For Esa, an oblique speaker top and curved sides are close to marketing propaganda, something that is clearly insufficient to solve the complicated problems of internal standing waves as something rather more complicated than generally believed. A 45° partition installed at the bottom of some earlier Esa cabinets turned out inadequate for eliminating standing waves generated between top and bottom panels. Simply removing parallel cabinet walls won't solve the problem since, according to Esa, tunnel (pipe) resonances arise in systems where one dimension is much longer, e.g. in speakers whose height is far greater than their width and depth. If in such speakers both the front and back walls are
tilted however, then together with a 45° partition, standing waves in the vertical dimension will be effectively eliminated as not only won't there be parallel walls but the distances between them will clearly change. About the remaining standing waves between parallel side walls Esa isn't concerned because they are less harmful and comply with wavelengths which can be addressed by appropriate damping methods inside the cabinet.

Whatever the explanation, Esa's ideas seem to work in practice if a lack of internal standing waves means fewer cabinet resonances. The cabinet of Credo 4 is completely inert. It's puzzling not to feel anything at all with the hands on the cabinet no matter how much bass the music contains. Over the past 15 years or so, I hardly remember another speaker whose cabinet was deader than the Credo 4.