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Resonessence Labs INVICTA Mirus Pro review

Game time. I’m going to describe an audio product, and you try to figure out exactly what I’m talking about. If you keep up with the latest and greatest by reading DAR, this should be pretty easy for you.

Ready? Ok, first clue – it’s a DAC, but also more than a DAC. Intrigued already, right?

More clues: This device has staying power – it’s often described as being on the cutting-edge of digital audio design, despite launching several years back. It has won an abundance of awards, including significant praise from this site’s publisher. Construction is handled on the North American continent rather than outsourced elsewhere.

Care to take a guess? Let’s nail down a few specifics. Our mystery DAC sells for US$6000. It has an HDMI port and an SD card slot — both highly unusual for this product category. It sports a powerful, updatable FPGA running custom code. End users reported significant improvements to SQ from updates applied to earlier iterations.

On basic functionality and features, that’s all she wrote.

PS Audio DirectStream? It ticks the boxes on all of the above. A great guess…but incorrect. The product under consideration here is Resonessence Labs’ Invicta Mirus Pro.

Though probably not as far-reaching as the DirectStream in terms of user-base, the Invicta line has nonetheless become a source of sonic truth for a good number of satisfied users, including yours truly. It’s been my reference DAC since it first launched and I have yet to come across anything that might supplant it – despite trying dozens of competitors, many of which cost quite a bit more. For this reviewer, the Resonessence DAC feels like home.

Some history. Resonessence Labs launched their very first product back in 2011. Mainman Mark Mallinson was fresh from his gig as operations director at ESS Technology, which had then just begun to take the audiophile world by storm with their range of Sabre DAC chips.

With several keys folks responsible for those Sabre DACs, the Resonessence Labs team came together. Not consultants or junior engineers but patent holders in many key aspects of ESS intellectual property. If anyone could extract maximum performance from these ICs, it would be this team.

Resonessence Labs has always preferred not to name names; and I’ll continue to respect those wishes here, but trust me when I reiterate: this DAC box manufacturer comprises key ESS players who know the Sabre DAC technology better than anyone.

That’s critical intel because Sabre DACs can reportedly be rather difficult to work with. Plenty of companies utilize them in their audio products. And some achieve great sound. Quite a few others do not. Could this be why many talk of “the Sabre sound”? A conclusion arrived at prior to exposure to considerably better-sounding implementations.

Let’s talk product evolution. Invicta first launched as an all-in-one unit with integrated SD card playback, D/A conversion, pre-amp capabilities and dual headphone outputs. Despite the onboard headphone amp being exceptional, a good portion of users didn’t seem to need it. This led to a fork in the road: the Invicta would remain in the lineup whilst a new model – the Invicta Mirus – would arrive sans-headphone output, with the headphone output’s ESS decoders redeployed in the main circuit. In other words, all of ESS’ processing power could be brought to bear on the line-outs (balanced and single-ended).

In late 2016, both models were upgraded to Pro status, their decoder chips jumping from the original flagship ES9018 to the latest ES9028Pro. While most DAC chips are stereo designs, the ES9028Pro sports 8-channels. So in the Mirus Pro we’re looking at 16 total “channels” divided by two for stereo use. Or, put another way, 8 “DACs” per channel. I like to call it Octo-mono.

Though the DAC chip itself is an important component of any D/A converter, there’s really a lot more going on. Especially in a complex device like this. Invicta has an FPGA “engine” with proprietary code executing tasks in the software domain, all for our sonic benefit. This aspect, probably more so than the DAC chip itself, could be considered the true heart of the device, with the designer going so far as to call it a “platform” in one of our earlier conversations.

Platforms are generally meant to be built upon. This one is no different. Invicta has undergone several FPGA-based updates over the years, each of which significantly elevated audible performance. Things seem to have matured enough – and to the point where we might not necessarily expect further upgrades of a similar SQ-lifting caliber (but I’d happily be proven wrong).

Proprietary code supply doesn’t end there. Rather than the usual USB solution from a third party provider (like the popular XMOS), the Mirus Pro sports USB hardware from Cypress Semiconductor, running custom code for asynchronous operation up to 24-bit/384kHz or DSD128. Users get their choice of seven digital filters, five of which are proprietary Resonessence creations. As is almost always the case with selectable filters, the differences are very subtle – more noticeable after long-term listening. I’ve settled on “Pro Minimum Phase Slow Roll Off” as my favorite, with “Pro Linear Phase Apodizing” a close second.

Device control happens via the front panel or handy Apple remote. Navigation is handled using the OLED or, better still, an external monitor driven by the HDMI output. In the latter case, hi-res album art makes an appearance, and large collections become more easily navigable. It’s no Roon, but those faithful to old-school folder/file browsing will feel right at home. If nothing else, you’ll want to keep a card full of your reference tracks in the SD card slot.

Sound? Summing up the sonic character of this full-featured device is inherently complex – there’s just so much ground to cover.

Let’s start simply, with absolutes. Across a wide variety of ancillaries, I felt like the Mirus Pro was more sonically malleable than other DACs. By that I mean it contributed less to the system signature than, say, a dry Benchmark, a meaty Luxman, or a sprightly Chord device. When Mirus Pro pairs with a sufficiently high quality amp, the transducer becomes by far the largest arbiter of sonics – plus with the room if we’re talking speakers. Mirus Pro comes closest to the old amplifier goal of “wire with gain” than any DAC I’ve heard in my system.

Is that a good thing? In this case, yes. I’ve heard devices described that way in the past which I didn’t end up loving – the Benchmark DAC 1, early dCS devices and many of the more recent Esoteric DACs and players. Manufacturers claimed total sonic transparency, yet all leaned toward the cold, clinical, analytical side of life — not my cup of tea. The Resonessence Labs ‘house sound’ doesn’t fall into that camp.

I find the Mirus Pro to sound transparent, resolving, and extremely fast, but it doesn’t beat you over the head with these qualities. Nor does it filter everything through that same lens. If I throw on some Matumbi, Carpenter Brut, Shai Hulud, or Little Brother, I don’t WANT every flaw in the recording under a sonic microscope, as if to berate me for not choosing more authentic “Audiophile-Approved Music”. Just give it to me straight, with all the fire, density, soul, and grit inherent in the record. Don’t gloss over anything, but don’t rub the flaws in my face either. Mirus Pro walks a fine line, one that many DAC manufacturers shoot for but few realise.

That’s not to say the Mirus Pro can’t sound absolutely stunning with quality material. The Reference Recordings HRx version of Malcom Arnold: Arnold Overtures is absurdly dynamic, and the Mirus Pro unleashes the full potential of this masterful release. Texture, soundstage depth, scale, extension for miles in both directions… the Resonessence flagship nails it all.

Ditto with Eric Bibb’s track “Where the Green Grass Grows”, which to my mind is among the most natural recordings you’ll find anywhere. The DSD128 version is a go-to, not for “you are there” realism but “they are here”. Close your eyes and drink it in, the Mirus Pro lets it flow.

Or, if you really want to have your expectations blown to bits, switch over to the 16/44.1 release of that same track, and marvel at how close it comes to the DSD version. There’s a difference, yes, and it favors the hi-res option, but I can confidently say this: if the majority of CD releases sounded this amazing, there would be little need for fancy formats.

SD Card playback is, if I’m being picky, probably the best way of getting the best sound from this device. Fun fact: the entire datapath chain is custom designed and implemented in the FPGA and includes writing the SD Card controller at the logic level. Here Mirus Pro has 100% control over the data flow from end to end.

Compared to this DAC’s other inputs (BNC, TOSLINK), the SD card offers a small but often worthwhile improvement in realism, particularly with soundstaging and imaging performance. All the “legacy” inputs sound fantastic, likely another upside of Resonessence Labs’ proprietary FPGA code. The USB in particular seems pretty much immune to USB decrapifiers. Feel free to run it naked, connectedly directly to your source.

Preamp results are a little more mixed. For well over half the volume range, Invicta’s 32-bit control scheme is completely transparent when attenuating Redbook material. Below that, things become (theoretically) lossy. Stay above 30% and you won’t hear the degraded sound quality of deep downward attenuation.

In practical terms, your amp and speaker sensitivity, plus room size and listening habits, will determine this for you. Active monitors tend to be great candidates – set their levels in such a way that the Mirus Pro volume never goes too low, and the result is exceptional. Traditional amp/speaker combos can work too but much depends on loudspeaker and amplifier input sensitivity.

Last year, I achieved the absolute best sound I’ve ever had in my home by pairing the Invicta Mirus (before the Pro upgrade) with the stunning JansZen Valentina Active hybrid electrostats. Playing music from the SD Card slot, this simplified system bested many of the more expensive and complex playback chains enjoyed previously. The result was more than a little comical: a bunch of other components in the hifi rack instantly rendered surplus to requirements. Back then, I bore witness to endgame performance – if I quit the audio review game tomorrow, I’d settle down for a lifetime of listening with the Resonessence Labs and JansZen combination. I tried adding several very nice preamps to the mix but all detracted from the purity of presentation. With the Pro upgrade adding very real improvements over the standard Mirus, I can only imagine the sonic fireworks that might ensue.

On the flip side, I’ve also assembled a recent system in which I prefer outboard pre-amplification. With Mirus Pro directly driving the Merrill Audio Thor monoblocks and paired with Usher Dancer Mini One DMD speakers, I felt the system was a little lean regardless of volume setting. Inserting a Modwright SWL 9.0SE preamp into the chain brought more tangibility and body to the sound, and I very much preferred keeping it in the chain.

Comparisons. How does the Mirus Pro stack up against the competition? $6,000 isn’t cheap, and readers are likely wondering if they can reach similar heights for less dough. I have about a dozen DACs here at any given time, so I figured it would be illuminating to spend time teasing out the Mirus Pro’s performance relative to other pieces.

In that context, the supremely transparent Pass Labs HPA-1 headphone amp becomes the ultimate evaluation tool. After level matching each DAC, A/B selection is handled with just the push of a button. I used a variety of my favorite headphones – Sennheiser HD650, HD800, and HD800S, HiFiMAN HE1000, AKG K812, Enigmacoustics Dharma, and the MrSpeakers Ether C.

For curious readers who care about such things: I used a Core Power Technologies Equi=Core 1800 power conditioner, with Cabledyne Silver Reference for AC cables and BetterCables Blue Truth II for everything else. Feeding digital to both DACs was a SimAudio Moon Orbiter which handily sports optical, coaxial, BNC, and AES digtal outputs. These outputs are all on equal footing at the transport level, so I fed each DAC the type it seems to prefer. Perfect comparison? Nope. Close enough? I think so.

The Mirus Pro sounds more coherent than Auralic’s popular Vega. The Chinese contender is a bit more lit up, effervescent, and wiry than its Canadian counterpart. A hasty listen might imply more detail, but this could be illusory – the Mirus Pro is just as resolving, and at times even more so, yet proceeds in an less forced manner. It has flow, an absence of which being my chief complaint about the Vega. The Auralic remains an excellent DAC but I can also see it eventually becoming the weak link in a well-planned system. It remains to be seen how the upcoming Vega G2 will fare, considering its price increase which brings it within spitting distance of Resonessence Labs’ flagship.

A comparison with Mytek’s Brooklyn shows me how dialed-in the Mirus Pro sounds in terms of contrast ratio. I don’t find the Brooklyn to be as fatiguingly bright/etched as its older sibling the Stereo192, but it does still give me some treble trouble at times. Mirus Pro offers superior fine-detail extraction and in an effortless fashion – qualities that benefit long-term listening. With the Brooklyn, I tire of Tiger Okoshi’s trumpet after about an hour, or perhaps more swiftly when using the HD800 or Dharma. Mirus Pro gives me more lifelike bite and extension paired with all-day listenability. In addition, I find the Brooklyn lacking that special “something” when it comes to midrange heft. Mirus Pro is more weighty and involving. Unfortunately I have yet to hear Mytek’s top-dog Manhattan II. My impressions of the original version were not so positive, but for all I know that’s been rectified on the refreshed model.

Another worthwhile comparison presents itself in the form of Resonessence Labs’ own Veritas – a model stepped-down from the Invicta line which sells for $2850. Veritas could rightfully be considered a younger sibling, which keeps the core sound but strips away the extra functionality. And it sounds fantastic. You get quite a good amount of the Mirus Pro sound for less than half the price. So much so that, initially, I thought it might be hard to recommend the higher-end model.

Further listening exposed differences of sufficient magnitude that justify the price jump from Veritas to Mirus Pro. At least for me. You might find otherwise – and I won’t argue. For me, the key factor which pushes me to favour the Mirus Pro is what I’ll call “palpability”. The Mirus Pro has a richer, more tonally dense presentation, as well as more dynamic punch.  The Veritas is no weakling but it can’t match its bigger brother in reproducing the full “snap” of a drum kit – particularly the snare drum, complete with harmonic undertones stretching down below 200Hz. It’s the sort of thing I didn’t really notice until I played some tracks with drumming by Idris Muhammad, Billy Cobham or Simon Phillips. The Mirus Pro is just more convincing than its sibling, particularly at higher volumes. Factor in the SD Card reader and increased connectivity, and the flagship model is worth the stretch – again, for my particular needs.

Lastly, the previously mentioned PS Audio DirectStream. This comparison was conducted prior to the new Huron software update. My DirectStream ran Torreys – and it sounded damn fine to my ears. I’ve said it many times before, and I’ll say it again: DirectStream is an easy recommendation.

However, with back-to-back listening, I heard the Mirus Pro as a clear winner: more air, more depth of presentation, and greater delineation between instruments. Treble texture in particular was a class above, such that while Mirus sounded utterly lifelike, DirectStream at times wallowed in the sonic equivalent of the Uncanny Valley.

Interestingly, the gains ascribed to the latest Huron update seem very similar to the improvement I hear by switching from the (Torreys equipped) DirectStream to the Mirus Pro. It seems to me that, after years of FPGA code tweaks (and some hardware upgrades on the Resonessence Labs side), both devices may have ultimately landed at roughly the same destination. I’ve yet to confirm with direct comparisons but on a conceptual level, I find this very intriguing.

Final Thoughts. Every music lover has at least a handful of albums and tracks which are uniquely special to them. Some of these are tied to a specific time and place: The soundtrack to your first kiss. The song that first inspired you to take up the guitar/piano/tuba. The favorite album of a close friend or loved one. In other cases the music just moves you in a certain way, and maybe you can’t even explain it. All you know is that you can play this music at least one a month, every month, for the rest of your life, and never tire of it.

My list of special music spans the gamut – Soundgarden’s Superunknown. Cosmogenesis by Obscura. What’s Going On by Marvin Gaye. Haydn’s Symphony No. 94 (specifically the Colin Davis version, though I dig the Jochum too). I Against I from Bad Brains. BT’s ESCM. Some of it well known and some less so, all of it has personal deep significance, and therefore earns a permanent spot on the rotation (often to the chagrin of my wife and kids).

Some audio gear has a special place in our personal history as well. I can already wax nostalgically over my first real Sony Walkman, which was a revelation after putting up with a quirky “Realistic” brand portable cassette player for some time prior. My first time with the original Technics 1200 (fabulous!), my first CD player (a Sanyo, though I don’t recall the model), the Creative Zen Vision M (30GB worth of music in my pocket, and a brilliant color display!) – all of these stand out in a sea of equipment purchases spanning decades.

It may be too early to tell, but of all the many DACs I’ve owned thus far, the Resonessence Labs Invicta line seems destined to join this small list of special gear. I’ve relied on it since it first launched in 2011, and have really only gone without it during the few times I’ve sent it back to home base for an update. Other excellent high-end DACs have since come and gone: PS Audio’s DirectStream, Exogal’s Comet Plus, the APL HiFi DAC-M, the Metronome C8, Bricasti’s M1, and Modwright’s Elyse – all of which I can heartily recommend. But none have quite moved me like the Invicta.

Others, such as the BMC UltraDAC and Cayin’s versatile iDAC-6, have earned a spot in my rig by offering an interesting counterpoint. They do things differently enough to justify their spot on the rack, despite my preference for the Resonessence Labs device in absolute terms. I think it’s useful, particularly while wearing my reviewer hat, to work with a variety of options. When it comes to ultimate fidelity for personal listening, the Resonessence Labs Invicta Mirus Pro is my first choice.

Further information: Resonessence Labs

Written by John Grandberg

John Grandberg

John Grandberg is a US-based audio journalist who has been immersed in the scene for over a decade. A recovering percussionist, he has a particular affinity for headphones and associated gear, about which he also contributes to InnerFidelity on a regular basis.

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