Nordost Sort Isolation System

A Trio of Options

Equipment report
Equipment racks and stands
Nordost Sort Isolation System

Why should we spend valuable time and money researching and acquiring aftermarket resonance-control devices? Because they can bring about substantial improvements in system performance. While I’m not wild about adding another complexity to my system or finding more ways to spend money, I am also results-oriented and have heard truly remarkable sonic improvements through the careful application of resonance-control devices—not only in my own system but in other systems as well. In some cases, they have changed the treated system from aggressive and rhythmically stuttering to neutral and wonderfully free-flowing.

In my experience, the first rule of using aftermarket resonance-control devices is to experiment. Place footers in different locations under the equipment or try orienting them up and down. Try different shelves. Try different combinations of the two. What works with one component may not work with another. The resulting interactions among components, footers, and supporting structures—including the room—can vary greatly. The basic protocol applies: Alter only one variable at a time and use the A/B/A comparison method. It takes time and effort, but the results can be worth it.

Nordost offers three resonance-control devices as part of its Sort System line: the Sort Kone (four models, for use under electronics), Sort Füt (height-adjustable heavy-duty feet used under racks and speakers), and Sort Lift (cable lifters). If you haven’t noticed, Nordost uses Scandinavian words in its product names. Nordost means northeast in all of the Scandinavian languages. Sort means black in Danish, a reference to “black background.” Nordost makes products that are designed to reduce underlying noise artifacts, which results in a “darker background.” I can verify that all three of the Sort products do just that to varying degrees, which I will cover with each product below.

Sort Kone
All Sort Kone models share the same basic design; their materials and prices differ accordingly. AS ($70, not supplied for this review) uses an aluminum post and base with a hardened-steel coupling ball. The other three all use a ceramic ball instead of a steel one, but their posts and cone base materials differ: AC ($85 per unit) = aluminum; BC ($149 per unit) = bronze, and TC ($370 per unit) = titanium. Rather than attempt to isolate the supported component from external vibrations, Sort Kones are designed to create an effective mechanical grounding path for the resonances within the electronics and shunt them into their supporting structures. Nordost says the Sort Kones act like a diode, letting unwanted vibrations drain out of the electronics but preventing extraneous vibrations from coming in. The instructions recommend positioning the cones with their points facing upwards, touching the bottom of the component. These “points,” by the way, do not terminate in a sharp tip but in a truncated cone—a flat, disc-like surface that is about ¼" in diameter. The instructions also give some helpful tips on where the user should place Sort Kones for maximum performance, such as under transports, transformers, and output tubes—i.e., parts that are prone to generating strong vibrations. I followed all recommendations and used three cones per chassis. I did not experiment with a four-cone configuration.

Do Sort Kones reduce apparent background noise? Yes. All three auditioned models reduced haze between images and throughout the larger soundscape. They helped contribute to a more organized and less splashy presentation compared to most of the tested components’ stock feet. As a result, images were more focused and the whole listening experience became more relaxed and involving. In ascending price, each model more effectively brought forth details and spatial information. Each also tended to change the apparent tonal center of focus in the following ways: AC seemed to strengthen the lower midrange and correspondingly reduce the upper midrange and lower treble, as if it had applied a slight so-called “BBC dip” (2kHz–4kHz) to the sound; BC seemed to widen the component’s effective operating zone and moved the tonal emphasis closer to the center of the midrange, reducing the BBC dip effect but not completely eliminating it; TC was by far the least colored and most rewarding musically. It seemed to allow its supported component to retrieve details and portray dynamic contrasts markedly better than the other two models. TC costs a lot more than AC or BC, but its performance jump is commensurate with its price.

I compared all three Sort Kone models to Stillpoints Ultra SS footers ($249 each) under every component in my system. (One component was tested on different shelves.) I also compared the Sort Kone models to Ultra SS in a friend’s system under his Esoteric X-01 D2 CD/SACD player with completely different shelving and room characteristics than those of my system. No matter the component or supporting shelf, the results were consistent in the two systems. Stillpoints did not alter the apparent zone of tonal emphasis, except to allow the components to play better at the frequency extremes. This made bass lines a bit more defined and extended, and upper-frequency definition and “air” more apparent. With the Stillpoints, some of the musical verve and immediacy also returned, whereas the Sort Kones—including the TC—tended to tame some of the music’s spontaneity and rhythmic momentum, while reducing background haze.