Auralic Aries G2.1 vs. Grimm MU1

[JemHadar]

Going on these field trips with Bart is always a blast. When he invited me to join him in assessing the Grimm MU1 versus the Auralic Aries G2.1 it was definitely something to look forward to.

Although the gear used in the comparison, bar the Auralic and the Mola Mola, was unfamiliar to me, the ability to swap out and replace components made it easy to pinpoint any changes. Not that we ever went back to the Auralic after the MU1 had strut its stuff.

Before delving into the Grimm MU1 proper, some observations about the complete system.

The HEGEL H590 is a mighty fine piece of kit. The internal DAC is most certainly not an afterthought as a direct comparison with the Mola Mola Tambaqui illustrated how brutal and unforgiving the law of diminishing returns can be. The HEGEL DAC’s presentation was more forward and narrow/intimate versus the Tambaqui’s open, expansive but slightly more distant soundstage. But we are talking subtle differences here as both DACs left nothing to be desired. It would all come down to personal preference. If you are considering an integrated amp the HEGEL H590 is a worthy and impressive contender for sure.

I appreciated the midrange and treble of the Vivid Audio Kaya45’s, however their compact size did not deliver the heft and impact in the bass that would be more desirable with bigger listening spaces such as the one at “Listening Matters”. It is just physics at work and not a critique of the Kaya45 abilities as such which probably are more aligned with smaller spaces. As Bart owns Vivid speakers and is familiar with their sound, the benefits of using them during the demo outweighed the cons.

I use an Auralic Aries G2 as wireless Roon Endpoint, paired with a McIntosh MDA1000 DAC and MXA60 integrated, in my Man Cave/Homework Office to great satisfaction. However in this particular demo setup the Aries was, dare I say, slightly underwhelming...and that was before having heard the Grimm MU1. Not that there was anything wrong with it, it was just OK, delivering the performance one would expect at its price point.

The MU1 on the other hand...it literally just took the first notes of a track to realise that this was something different entirely and very special. I will spare you the audiophile babble and leave it at this: the Grimm MU1 makes you want to listen to music more. It allows for the music to seduce you and draw you in. Through a sense of presence and involvement the music establishes an emotional connection that just wasn’t there with the Aries.

By Ben van Leliveld’s reckoning, it would take the full Auralic stack with clock and upsampler to approach or match the performance of the MU1 and then some. This realisation shines a different light on the asking price for the MU1.

The design brief of the MU1 is unique though and will benefit specific use cases more than others.

If you own Grimm Active speakers and wish to embrace the world of streaming and get lost in the Roonverse in particular, the MU1 is a no-brainer. I have experienced this combo at two separate occasions and the performance is just off the charts. Don’t take my word for it; if you have to chance to audition such a setup in optimal conditions, you are in for a treat.

If you are intent on using the DSP features of Roon and/or own a library that requires Nucleus+ type performance, the MU1 most definitely is not for you. As the resident NUC does not feature any form of active or extended passive cooling I can only surmise it is a very low power version of Intel’s Next Unit of Computing. Taking a tally of the number of endpoints the MU1 will have to service seems prudent too.

Although the chassis is rather nice, the top mounted control wheel could make rack mounting a challenge. A provision to add an infrared cell is made. However at this price point a remote or an app that allows for changing the inputs from your listening position should just come with the package.

For all its technological prowess, the user interface of the MU1 is rather clunky and feels like an afterthought at best and an unfinished project at worst. As I understand it, development is continuously ongoing and improvements are bound to be implemented. But I cannot shake the feeling that despite years of development the product could have benefited from some TLC finishing touches as far as the user experience goes.

Some design choices are, IMHO, a bit idiosyncratic. The deliberate choice not to display cover art (in its defense; possibly the spec of the display used is not suited for this). The choice not to support USB audio which precludes the use of e.g. Dynaudio hubs, reasoning being that USB negates the magic sauce of the MU1. That might well be, but it limits the number of use cases; some of these use cases being more about convenience than hardcore performance.

Now what is this magic sauce that elevates the MU1 to these extraordinary heights of performance; that would be a combination of Grimm clocks and bespoke up/down sampling algorithms running on a FPGA chip. The idea being that the heavy lifting is done by the MU1 relieving the DAC of these duties.

To reap maximum rewards the use of the AES3 outputs is recommended as the serial data stream contains the bit clock. Given that the DAC slaves to this bit clock, it will benefit from its superior timing. Best to check the internal architecture of your DAC because not all DAC’s will slave their clocks to bit clocks embedded in the data stream and only use it to buffer data correctly.

Similarly, as the Roon RAAT protocol moves buffers of audio asynchronously, the clock advantage for the DAC is lost when a Roon Ready DAC is connected through Ethernet. However, from the demo, I can only conclude that it is the nature of the up/down sampling calculations of which the outcomes are reclocked by the Grimm clocks, that make the MU1 outstanding, regardless of how the bits arrive at the DAC.

I wonder if the inclusion of the Roon Core is absolutely necessary for the whole unit to function. A version without the Roon Core, but with Roon End Point (rendering) capability, at let’s say half the price, would give the dCS Network Bridge a run for its money. As such the Grimm MU1 occupies a very specific place in the Roonverse with no real DAC-less competitors as far as I can tell.

The Grimm MU1 is a music player that makes no apologies for its idiosyncratic way of doing things. It marries a Roon Server of moderate ability with an exceptional up/down sampling solution, packaged in an elegant one box offering.

If you are a Grimm speaker user the MU1 is as good as unavoidable. Besides Grimm speakers, depending on the DAC or Roon End Point one uses your mileage may vary, but no doubt it will delight those seeking an emotional connection with their favourite music but not requiring Nucleus+ type performance.

If you haven’t done so already, do check out the releases on the trptk label of which Ben van Leliveld, our host for the day, is the driving force. Trptk releases stunning recordings of world class performances.

It was a fun day and congratulations to Bart with the purchase of his Grimm MU1.

Kudos to Ben van Leliveld and his crew for taking care of us.