YG Acoustics Sonja 1.3 loudspeaker

The advertisements run by Colorado manufacturer YG Acoustics in 2008, when it launched its flagship loudspeaker model, the Anat Reference II Professional, unequivocally claimed it to be "The best loudspeaker on Earth. Period." They caused a stir. The YGA speaker cost $107,000/pair at the time of Wes Phillips's review in the March 2009 issue (). Wes didn't disagree with the claim, concluding that, "Like my pappy used to say, it ain't braggin' if you can actually do it."

To riff on Wes's conclusion, "If it ain't broke, it don't need fixin'." So I was somewhat puzzled when I first saw the Anat's successor, the Sonja 1.3, at the 2013 Consumer Electronics Show. The Sonja 1.3 comprises the Sonja 1.1, the top module, which can be used on its own and costs $38,800/pair (footnote 1). Adding the upper woofer module gives you the Sonja 1.2 ($72,800/pair), while completing the package with the lower woofer module results in the Sonja 1.3 ($106,800/pair).

Superficially, the new speaker looks identical to the older one: the same height, the same form—three separate modules constructed from aluminum panels mounted atop one another—and the same drive-unit array: a 1" silk-dome tweeter mounted within an almost circular waveguide between two 6" midrange drivers, and two 10" woofers. But on closer inspection, it became apparent that the Sonja 1.3 is, in many ways, a completely different design.

The Sonja . . .
The modules of the Anat Reference II Professional were flat-sided, with the HF/MF module rectangular and the two woofers truncated pyramids of different heights but identical volumes, which gave the speaker's appearance a Bauhaus flavor. By contrast, the Sonja 1.3's modules feature subtly radiused side panels, the increasing radius of the lower modules producing an elegantly concave profile. The woofers are no longer powered but passively crossed over, the crossover for both modules residing in the bottom one. (When just the Sonja 1.2 is purchased, the low-frequency crossover is housed in the 1.2 woofer module; this is replaced by a blanking plate when the 1.3 woofer is added.) The crossover filters are a proprietary topology, said to add in-phase in the overlap regions, and use expensive, close-tolerance Mundorf capacitors and "Zero Ohm" inductors. One toroidal air-core inductor is wound in-house by YGA, and the Sonja's internal wiring is all Kimber Select.

Most significant, whereas the Anat and its variants used paper-cone midrange units and woofers, the Sonja's drivers feature the BilletCore diaphragms that made their appearance toward the end of the Anat's life. Each cone begins as a circular blank of 6061 aluminum alloy, an aircraft-grade metal that finishes well and doesn't corrode like harder aluminum alloys. A five-axis CNC machine first balances the blank, then increases its rotational speed so that metal can be cut away to produce the finished cone. It takes about three hours of machine time to produce the woofer cone, which has a thickness before anodizing of 0.25mm, this down from an initial time of eight hours. To produce a midrange cone, which is 0.2mm thick, takes about 90 minutes (both times including setup). The finished cones are sent out for hard anodizing, then shipped to Denmark with the surrounds to be assembled into complete drive-units, the Danish company providing all the "soft" parts, such as the spider.

The final woofer cone weighs 46gm; for reference, the cone of the 10" woofer used by KEF in its R207/2, which I reviewed a few years back, including the voice-coil and its former, weighs 40gm. There is therefore a tradeoff between increased mass and reduced sensitivity with a machined-alloy cone. However, YGA's founder, Yoav Geva, feels that this is worthwhile, given that the BilletCore cone is going to be truly pistonic not only throughout its passband but well beyond it. The use of machined metal unstressed by stamping or extrusion makes the cones extremely rigid and strong—the midrange cone has a mass of only 8gm, but can take 1000 lbs of vertical load without flexing.

Not only the cones, but all the metal parts in the Sonja, including the trim rings around the drivers—even the biwiring binding posts—are made by YGA. The aluminum panels that form the enclosures are milled from large sheets of aluminum.

I visited the YGA factory just before writing this review. It's an impressive operation. Raw aluminum-alloy rods, bars, and sheets enter; finished speakers and bags of aluminum swarf and scrap leave, the former to dealers and distributors, the latter to a recycling center. YGA's two expensive CNC machines run flat-out for two shifts every day, even machining away the copper between the traces on the circuit boards for the crossover filters.

Having seen YGA's capital-intensive operation, I am surprised not only that the Sonja 1.3 doesn't cost more than it does, but also that it costs slightly less than the company's earlier flagship model.

Setup & System
YGA's Dick Diamond and Kerry St. James delivered the six aluminum flight cases containing the Sonja 1.3s and, much to my relief, insisted on setting up the speakers in my listening room all by themselves. With each complete speaker weighing 506 lbs, I had been wondering how they were going to move them.

The answer: To place the 1.2 module atop the 1.3 module, then crown the array with the 120-lb 1.1 module, they used the hand-pumped, handled suction cups used to lift large sheets of glass. Then, with the speaker assembled, they slid Teflon furniture-moving coasters, fitted with Delrin inserts, under the four spikes. It proved surprisingly easy to slide the speakers around on these coasters, to find the optimal positions in the room. Once Diamond and St. James had proclaimed themselves comfortable with the setup, they took the suction cups and coasters away with them, meaning that I was able to do no further fine-tuning of the speaker positions.

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Footnote 1: This price is with the internal, 65Hz high-pass filters fitted. A pair of Sonja 1.1s without the filters costs $34,000.
Source : stereophile[dot]com