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Synergistic Research Foundation SX interconnect and loudspeaker cables

Synergistic Research Foundation SX interconnect and loudspeaker cables

We tested Synergistic Research’s original Foundation series of cables back in July 2020 (hi-fi+ Issue 185). A lot has happened since then, and the Synergistic Research Foundation SX series is the result. They remain the one above the entry-level range to Synergistic Research’s extensive line of tuning and power products. We’ll look at yet more of those in our next survey of the Foundation SX line.

To recap, Synergistic Research makes a range of components that treat the system rather than components in the system. The company makes power products, equipment supports, acoustic treatments, fuses, cables and more.


The original Foundation Series cables featured 6N purity pure silver conductors. These featured Synergistic’s own handmade Air String geometry. It also used the company’s UEF (Unified Energy Field) Matrix shielding in a grid pattern inside the cable. Foundation signed off with a graphene sleeve extending around the connector itself. The RCA cables used four of these Air String conductors per channel while the XLRs used six. All of these conductors were woven in an air dielectric and wrapped in a tight braided jacket. The loudspeaker cables looked almost identical to the interconnects, using identical materials, techniques, and jacketing. The positive and negative conductors are separated, with two distinct conductors for each speaker terminal connection. This means four cables per channel for bi-wire, six for tri-wire, and so on.

Foundation and Empire

These cables were damn good, but they were also an introduction to the whole empire of Synergistic Research’s systematic treatment of an audio system. As a result, the cables must work independently of Synergistic Research’s other treatments, but also act in harmony with them, and work with the broadest range of systems from affordable to distinctly high-end.

Covering all those bases was a tough call, but one Foundation did exceptionally well. And now it’s three and a half years later since its launch, and Foundation SX replaces the original. What’s changed… and why?

Second Foundation

The ‘OG’ Foundation was based on the technologies created for the higher-end Atmosphere X series cables. Foundation SX trickles down from the recent developments to the super-high-end SRX cable systems. The core construction of the Foundation remains unchanged. Still, it is treated with a new UEF Compound and subjected to a long-duration, high-voltage conditioning process that ensures the cable is correctly and consistently run in before it reaches the end user. The SRX project also helped create the latest UEF Carbon Tuning Discs, but more on these later.

The word ‘consistency’ is critical. Foundation worked both as a standalone single-cable upgrade and as a complete system cable rewire, but with Foundation SX, that latter all-Synergistic cable system makes even more sense. Yes, of course, you hear the benefits of one Foundation wire in the mix, but you hear the benefits even more directly if every cable in the signal path is singing the same song, and Foundation SX makes sure they all sing in harmony.

Foundation’s Edge

Used across the board, that synergy is met by some extraordinary levels of insight and detail for what is – by high-end standards, at least – distinctly affordable cables. You get more than a glimpse of the big audio picture here; with sublime soundstage width and solidity of images within that soundstage, frequency extension to make instruments with a high-frequency component sound natural instead of ‘tinny’ and ‘brash’. The cable is also analytical without being over-analytical, detailed without sounding ‘etched’ or ‘edgy’ and highly coherent and articulate right across the frequency range.

 There is one final question to address. Three and a half years later, would a Foundation owner be wise to upgrade to Foundation SX? Well, yes and no. Suppose you have upgraded some parts of your system to Foundation. In that case, the rest should receive the Foundation SX treatment, and you’ll likely upgrade the more essential parts of the system with SX, and the lesser-used components will end up with the original. But if you are thinking of changing Foundation for SX? Maybe. It’s better, and there are trade-in programmes, but I think a trade-up might be better.

Foundation and Earth

I almost missed the last bit of the test; the UEF Carbon Tuning Discs are tiny and extremely light… and there’s a purple and a gold one and some White-Tack in a baggie supplied with each cable. For a few seconds, I thought Synergistic had thrown in a couple of tabs of acid with the cable. I was about to tell them that I no longer go to Hawkwind gigs when I found out about the whole Carbon Tuning Discs thing. Back on planet Earth, they are fine-tuning devices that you stick to the strain relief of the cables that broadly speaking give you more soundstage depth (gold) or more detail retrieval (purple). That’s true ‘edge of my weird wide world’ stuff and makes me wonder if they are made of LSD, after all! Regardless the Discs do something and do it consistently.

Even if you ignore the discs, Synergistic Research’s Foundation SX builds on the strengths of Foundation. It, therefore, has the correct name. It’s a perfect foundation for transforming a system through Synergistic Research’s tuning systems. But, that holds even if Foundation SX is your only shot at coordinating the sound of a system. If you have no plans to explore the rest of the Synergistic Research catalogue, the Foundation SX cables harmonise and bring out the best in any system.

Price and Contact details

  • Synergistic Research Foundation SX interconnect cables: $699 (excl tax), £599 (inc VAT) 1m RCA (as tested)
  • Synergistic Research Foundation SX loudspeaker cables: $749 (excl tax), £650 (inc VAT) 8’ spade lugs (as tested)


Synergistic Research

Homepage – https://www.synergisticresearch.com


Interconnects https://www.synergisticresearch.com/cables/foundation-sx/foundation-sx-ic/


Loudspeaker cables https://www.synergisticresearch.com/cables/foundation-sx/foundation-sx-sc/

International Dealer List – https://www.synergisticresearch.com/dealer-list/

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