Stereo Sherlock & Wattage Watson. To prepare for Corelli's arrival, here are sundry tweaks and my take on their potency. I define tweak as a device whose removal doesn't interrupt the sound; or which requires only a quick rewire to revive the sound with one less thing in the signal path. Footers, racks, AC filters, network switches and USB bridges are all tweaks unless a DAC for example has no USB input. Now a bridge converting USB to S/PDIF is essential. Other tweaks are software audio players like Audirvana, Euphony or Roon. They aren't essential but can be useful upgrades like replacing a generic power cord with a better specimen. Relative to their negligible audible impact, to me most digital filter options seem ultra marginal. On audible relevance, I'd rate them dead last in fact. If our home/flat situates low-density rural to make our electro-smog exposure far lower than that of an inner-city apartment complex adjacent to big commercial users, network switches and USB bridges are next. How much their inclusion might otherwise matter I don't know. I've not lived in a city in a very long time. The same can go for AC filters. Their contribution's potency depends on how loaded down and polluted our power delivery is to begin with. But even in our 'lost sheep' zone I prefer quality passive power distributors à la Furutech to wall direct. It might surprise you that I find isolation footers particularly under full-range speakers and/or subwoofers more potent still especially on suspended upper-storey flooring. Just as obvious regardless of location are old-fashioned tone controls and their modern DSP-based EQ plug-ins. The latter and their room-correction cousins are arguably the most potent, surgically precise thus predictable of all 'tweaks'. Having previously reviewed Akiko's single €450 plug-in barrel dubbed Triple AC Evolution, I expected a more potent rerun to sit somewhere in the vicinity of wall-vs-distributor potency. Making definitive proclamations like "35% better" is impossible but I'll still try for a rough placement on my tweak gradient.

The following excerpt of a manufacturer's reply to this Michael Lavorgna review frames the conditionality of tweak review findings: "… as far as the Bonn N8 [a $549 network switch by Silent Angel – Ed.], I understand your findings. Having a completely separate building with a network dedicated specifically to your audio system is the ideal state of affairs and something that very few music lovers—myself included—can accomplish. Most of us have a house full of computer gear, televisions, cable boxes, phones etc. pumping noise onto their networks, all of which compete for bandwidth and create a hostile environment for delicate digital audio signals. It is for these individuals that Bonn N8 was developed and this switch should provide significant improvements in such environments. In the months since we submitted review samples to Twittering Machines, Silent Angel has developed more advanced and higher performance network switches, linear power supplies and assorted other products which might well improve your system performance…".

To paint today's picture still clearer, our present home isn't just in a remote location. Our Internet access hardwires to a fiber-optic module on a mast outside my office. Its feed to our provider's indoor router then continues hardwired to all computers via industrial CAT8a wire. We don't run any WiFi as a virtually ubiquitous source of electro smog. My cellphone hides in our car's center console rarely on. Whatever AC noise we're exposed to should be mostly of our own making. It'll be from the kitchen refrigerator, utility room freezer and boiler-room hot-water tank all permanently live. Washing machine and dryer are more big loads but only temporarily on. Likewise for sundry household appliances and lamps plus computers. It's arguably not the most lurid tell-all scenario into which to drop an esoteric AC conditioner to make a big splash. But if I could tell its insertion and removal by ear, how much more might it do in environments as described in Silent Angel's comment? Living rural on a barely traveled estuary frontage road has another advantage: low ambient noise. That's the silence when no music plays. In an inner city, that 'silence' could well measure higher than 40dB because it includes incessant background din. In my office and listening room, I measure less than 30dB. Lower noise means higher signal-to-noise ratio. Now little things matter more. Just as you can't see well through dirty glasses, you can't hear well with a noisy background. On that score our location is rather ideal to emphasize the effects of even minor tweaks. It's another variable to consider when you try to gauge how review findings might apply to your own situation. I believe this now covered all the small print we needed today. Action!

"The reference system consists of the new Virtuoso Soltanus ESL speakers that have been here for some time, a PrimaLuna HP integrated with KT150 tubes, Gryphon's Kalliope DAC, the new Audio Research PH9 phono stage and the Soulines Kubrick DCX turntable with ZYX cartridge. In short, a highly resolving yet not crazy money system that I'm very familiar with. The enclosed manual states that the Corelli takes a few weeks to stabilize yet the biggest change will occur in the first day. That's the biggest audio understatement I've yet heard. For the first fifteen minutes nothing much seems to happen though my wife made the comment, "hey it sounds a little smoother, what did you do?" Then the trip began. As that Tidal playlist continued, I swore that everything was sounding better, more homogenous, less grainy, more natural. Going back to the LPs I had listened to earlier, it was a night and day difference. Three areas made a major improvement: pace/timing, upper-frequency smoothness and the size of the three-dimensional sound field painted by the Virtuosos. For $2'000 with power cord, sign me up. Trying not to be taken in, I unplugged the Corelli and removed it from the system and things shut back down to pre-conditioning levels. A few game-on game-off cycles later combined with torturing a few good audiophile buddies, we've all heard the same basic effect. Just like that damn [Furutech – Ed.] De-Mag. At the end of the test session I'm definitely keeping the Corelli around. I still can't really explain why or how it works but it does."

Okay, that was vintage action from an old Jeff Dorgay review referenced in the YouTube video. But it sets the stage. I too got Akiko's €159 1.5m power cord to use with it. I also had thoughts going in. If I heard similarly obvious benefits on my downstairs source stack, my active AC/DC Vibex filter from Spain would still leak plenty of noise. Likewise for gear which plugs into passive Furutech bars with nanocrystal formula 2 aka NCF² elsewhere. It'd be a corollary perhaps for our Osmio counter-top water filter from the UK? That runs four different filter modules all aimed at different pollutants. A single one would be too lossy. With broadband noise above the audio bandwidth well into the GHz range, we probably shouldn't expect any one solution to address it all, either. As is, our multi-stage water purifier elements get changed out every six months. Hifi noise filters differ. They never clog up to need replacement parts. Set 'n' forget. Just then a reader email arrived. "I couldn't agree more with regards to hierarchy of tweaks. I've become highly reliant on creating convolution filters using Room EQ wizard with the MiniDSP microphone to upload to Roon. I can spend as much time dialing in these filters as messing with tweaks. It rendered a lot of previous expensive equalization games with cables vastly overpriced. Roon lets you A/B easily and I go from happy face to sad face when the filter is off. I also found that isolation under speakers (I'm on a second floor but never tested vs bottom floor) has come in second. My Balabo amp does its own AC line regeneration and my Mola Mola Makua claims to be AC line impervious. I have a custom 5KVA balanced isolation transformer but hear no difference with it." That was David Hyman, previously CEO of Pono who among other brands recently began importing Japan's Wellfloat isolators to the US.