I think what a lot of people miss is that the ADI-2 DAC isn't really aimed at the readership of this forum, although it's good that so many people like it.
It is a professional audio interface without the ADC functionality, and with a sonic signature designed to be as flat and as detailed as possible so that producers, mixing engineers and mastering engineers can make accurate decisions on the final musical product.
With that in mind I can believe that a lot of people find it not so punchy, or a bit thin in some circumstances. For me this sound signature is fantastic. I've not yet come across an audio interface that lays it out like this one, and it enables me to produce as a hobby knowing that whatever I do will work well with other listening gear.
Personally I don't like "HiFi" sounding gear like Chord or Audeze - it sounds artificial to me. Pleasant and musical, but ultimately lacking in realism from my point of view - I couldn't work with products from either brand. That said I do understand people who enjoy that flavour.
So with that in mind, if you're somebody looking for a device that will reveal everything, warts and all, then the RME ADI-2 will do that superbly. However if you're looking for something a bit more "HiFi" and coloured then "this is not the droid you're looking for".
Hi Slaphead,
I agree with your general ideas, and find it very right that you stress that the RME products belong to the pro audio world, unlike many products on this site.
"High-Fidelity", as the name says, means realism, neutrality. So, by this definition, products like RME ADI-2 DAC are actually truly High Fidelity, much more than most products here which are rather "audiophile" in the sense of "euphonic".
I think that the "audiophile" word is responsible for a lot of confusion.
It means only someone who likes audio a lot (thus would be ready to invest a lot of time and money for it). It was first coined in France, and was originally used for people looking after high fidelity (i.e. what the pro audio world like RME strives to). The problem is that the "audiophile" word is not synonymous with high-fidelity and was soon used by companies producing expensive products with a euphonic presentation, i.e. definitely not neutral, more pleasing than in reality, but then not high-fidelity.
So some people unconsciously use "audiophile" in the sense of high-fidelity while other use it with the opposite sense (euphonic) and some others are even inconsistent with themselves, alternating between the two perspectives (sometime meaning high-fidelity, sometimes meaning euphonic).
I think that you nailed a nice example with Audeze, I own several of their products of their LCD series, they are definitely not neutral, but I find their presentation often more pleasant for listening to metal music than a realist one (metal uses all the frequency range, the electric guitar can be quite fatiguing, but my Audeze LCDs help here with their large dip in the low treble), though I strive for neutrality. One most extreme case for me is the LCD-4, I auditioned several times some of them at my dealer,, once with the intent of purchasing it, yet it was so far off from neutrality that it was far beyond what I could accept. And yet it is very expensive (€ 5000 here in Europe!) and many audiophiles absolutely love its sound.
Re. solid-state DAC-amps I auditioned, an example of products in my experience which are rather euphonic [edit: was audiophile] than high-fidelity would be Questyle's, as opposed to RME's. I find them artificially thickening the sound, a bit like tube amps usually do.
Re. Chord products (owning a Mojo, and having auditioned several times the Hugo 2 and many times the Dave which I find fantastic for driving the Utopia), to me they sound neutral, but I also have a feeling as if they would embellish the sound, I can't explain it nor find a fault, it eludes me. (In general I absolutely hate their design and find them very unpractical, with a ugly, irritating color system, often lacking essential things like a volume knob or sometimes not being stackable like the Dave, etc.).
I often saw people arguing because they mean different things. It would be better if they would clarify whether they are speaking from a high-fidelity or from a euphonic [edit: was audiophile] perspective.
All the best and keep healthy,
bidn
[EDIT 26.03.2020 : I changed at some places "audiophile" into "euphonic", to make a clearer contrast with "High Fidelity"]