Resident tweak alarm. We use Franck Tchang resonators which work in the acoustic domain. Those could stay put. Their influence doesn't overlap with the LessLoss kit. Meanwhile for hifi power purity, a combination Vibex Granada/Alhambra DC/AC filter attends to very effective powerline noise attenuation, DC offset cancellation and generating the number of outlets our front end stack requires. The amp/s and subwoofer plug into their own wall outlets in the left front room corner. The sub's power feed is preceded by a single-outlet Vibex DC filter. That eliminates transformer hum from its Hypex plate amp which is mounted too close to the 12-inch woofer's magnet. Because Polish firm Verictum didn't want them back after their review, I also have three of their wood-ensconced HF noise filters. One each terminated in a small spade sits on the ground terminals of the Nagra Jazz preamp and Pass Labs XA30.8. This 'siphons off' HF energies roaming in the component's metal chassis and associated ground planes. One terminated in a US-style power plug occupies the 8th outlet of the front end Vibex stack to add the same thinking to my piggybacked conditioners. Also, three of Verictum's paperback-sized black passive filters squat atop two DACs and the Nagra. Those are topped by the mass dampers and RF/EMI discs which come with Artesania Audio's Exoteryc rack.

For between-the-cheeks action, remove the four long wood screws.

It went without saying. The Verictum/Artesania pieces would have to follow Elvis out of the building. Perhaps I even had to replace my Vibex kit with a basic outlet strip. Only that would create true ground zero for the FireWalls to solo their act. After all, these devices all operate in the same general vicinity of influence. They surely overlap. If I meant to fully learn what the LessLoss stuff could do, I had to eliminate help, interference and confusion from competitors. Back to basics would do just that. I'd thus compare my existing setup to replacing all the Verictum/Artesania with all the LessLoss solutions; compare a bare-boned power strip to the same power strip plus LessLoss; add the Verictum ground/power trio back in; and finally return to my existing 'full-bore' setup, then add LessLoss to see whether Louis' boxes could still assert themselves over and above installed highly proven competitors. Once I knew which scenario had the FireWalls speak loudest, I'd attempt to determine on which component they made the biggest contribution; and whether serializing a few on a single component outdid having each active component firewalled with its very own. From tool to toy box and back again was the basic plan.

Inside each Firewall, four of the thumb-print sized PCB are wired "in parallel, each in a different way because there are four ways to connect each one to deliver the lowest noise, lower than four in series all in the same way". A user can additionally plug one Firewall into another ad infinitum to presumably compound this action. Below is the Vibex front-end conditioner with add-on Verictum module; and next to it the amp/sub setup with a Verictum ground purifier on the amp chassis and the single i/o Vibex DC filter on the subwoofer's feed. Active components would be my usual iMac with 32GB of RAM and PureMusic set to power-of-two upsampling; Fore Audio DAISy1 DAC; Nagra Jazz preamp; Pass Labs XA-30.8 class A stereo amp; and Zu Submission subwoofer augmenting the EnigmAcoustics M1 monitors with Sopranino super tweeters. I also did a few rounds with the Gryphon Audio Diablo 300 and Pantheon combination.

But first, one word on fit'n'finish: a'okay. Shorter than a grown man's palm with outstretched fingers, logo deeply engraved without any fuzzy edges, solid oak nicely finished all around without any burrs or rough spots, the plug'n'play Firewalls looked and felt the business. Louis clearly cares about appearance and tactility. On that count, his devices delivered right off. For DIYers, here are the instructions.

To condense the outcome of my various listening sessions, we reach straight for the conclusion. On whether the Firewalls could still make a difference in my fully loaded context—one Firewall on each active component, another on the Vibex conditioner's IEC—the answer was an unexpected but unequivocal yes. Without them, the sound became more splashy, wiry, stark, hard and grainy. This got a lot more so with my subsequent scorched-earth move to a very basic power strip with no noise filters or conditioning of any kind, all additional EMI/RF tweaks stripped out of the system as well. Using that as my baseline for what we should really call bad digital sound, adding back just the Firewalls reinjected fluidity and smoother softness. It simply couldn't approach the fully loaded performance. However, just the Firewall effect on this basic strip was more potent than that of the Artesania Audio discs or Verictum devices. It moved the sound from a needly spitty emphasis on transients back into more bloom and decay for less steeliness. Casual audio lingo calls such steeliness etch. It's most easily heard on plucked higher strings but really permeates everything with overdone crispness. If you mistake that quality for speed, you'd call the Firewall effect calmer and more lingering float than pushy urgency.

Rebuilding my setup step by step back to full hog, I determined that in sequence of gravitas, it was Vibex, Firewall, Verictum, Artesania. Considering that the Verictum stuff was rather costlier than these LessLoss items, this spoke to good value for the Lithuanians (or poor value for the Poles). What I found fascinating and disturbing? My multi-pronged layered approach seemed endless. It destroyed the notion that any one filter could be of such bandwidth and potency as to render good add-ons ineffective, hence redundant. To reduce box count, expense and also to be flat done, one of course hopes otherwise. Yet the subjective evidence, of piling one clearly effective powerline solution atop another to still reap appreciable benefits, was undeniable. Drat.

On the matter of where, I couldn't decide between iMac and DAC as most important. Still, I would call these sources first responders, then the analog gear of preamp, amp or integrated. If one had just one Firewall, it makes most sense to plug a power bar or conditioner into it. Slaving multiple Firewalls in series seemed less effective than giving each component its own. Finally there's the perhaps peculiar notion which Edwin van der Kley Rynveld of Siltech and Franck Tchang of ASI stumbled upon separately. Whatever you do to both ends of a cable duplicates how this cable would behave were it made so all the way through. Placing one Firewall ahead of the conditioner and one in front of each component effectively terminates each power cord with LessLoss skin filtering on either end. That seems ideal. In the world of iPhone audio and earbuds, the notion of power cords and AC quality is absurd. That makes add-on noise purifiers the stuff of ridicule. Back in the realm of high-end audio meanwhile, a compact $410 sticker for the type of audible effectiveness I observed with these wooden modules meant good ROI. That the wood and its associated expense could be partly or wholly window dressing is simply good business. Surviving long-term on just sales of $198/ea. DIY modules seems too hard. In closing, LessLoss must have honed their Firewall tech since my first encounter with it. In their current form, these devices gain a very solid recommendation even if you've already invested in a proper AC conditioner. If you want your sound to be rounder, fuller, more fluid and suave, getting a few LessLoss Firewalls could be one demonstrable way forward. They were more effective than I expected. But wait, there's more...