Sorry, I was away for a while, I'm back now. Yeah I know what you mean for volume perceptively affecting low and high end, that is true. Damn evolution... Yeah I've heard of loudness compensation, to compensate for the evolution "mess up" xD.
If we're not a tad bit nuts though then what are we doing on this planet haha. Liquor-ing up heightens the senses, and I don't think you'll say no to my Manhattan once you try it
But, I might not be disappointed in you after all. I liked your and Svend P's persistence, it didn't align with what I was hearing for a reason. But I could tell of the way you were persistent and others, that there IS something missing in the equation here, not that you are wrong or something, and I would bet you for the audible difference I was hearing. Now I get it that the AVR and ADI-2 DAC are sounding probably exactly the same. Thanks for sharing the amp info too. Please read further
So, cause of all this feedback that I got here, I did deeper inspection and everything in my setup, cause things just didn't add up. Aaaaand, it turns out everyone that said the DACs should sound the same were correct. But also, I was correct as well in what I was hearing comparing the two, and how I described that.
Why? Well...... This pinched my nerve haha. The WiiM is plugged in the CD analog RCA input in the AVR, the RAW MDA-1 in the DVD analog RCA input, and I was switching between the two, sitting about 2.5m (7-8ft?) from the receiver. You could've shot me and I'd still tell you they didn't sound the same. Then, I came closer to the AVR so I can read everything that's on its display, not just the big letters.
I started rapidly switching between the 2 inputs from up close to look for any changes in the display. And god damn what a discovery... While everything else off, for some frickin' reason (probably the AVR thought it's a DVD and the audio will likely be compressed), it decided it's a good idea to candidly and automatically turn on Sound Retreiver ONLY on the DVD analog input where the RAW MDA-1 is connected. And the indicator that this is on, is probably 2x3mm big and in no way visible from a listening position 2.5m away. I turned that off and there it is... Try to tell the difference between the DACs now... I didn't even need a blind test to tell that they sound... yeah the same.
And the Sound Retreiver does exactly to the sound what I was hearing and describing so far. Punchy, different overall frequency response and with more attack. That's why I was so resistant and "nope they don't sound the same"... Well they really didn't with Sound Retreiver on on one input only... That off and there's no audible difference.
I had to break 2 chairs out of frustration for that undercover Sound Retreiver, it was fun... hahah I'm kidding that's expensive, I only broke one nice glass..... ok I'm joking again
So thanks again to all for all the help and the persistence, it paid off.
But that PEQ in the WiiM... man is it good, it also has the widest Q I have seen outside a computer, goes as wide as 0.10. I boosted a little around 25Hz and 18kHz with a wider Q to compensate for evolution issues xD, and the setup sounds even fuller and better than ever.