First let me say that I know there are those out there that will call my assessment between AirPlay, at CD quality, and Wi-Fi at Hi-Res quality, bulls***. And that's okay. I realize that I cannot qualify my assessment with scientific measurements, or quantitative data. I can only share what I believe I heard. It is purely a subjective finding.
I listened to two different songs;
So What, from the album
Kind Of Blue, by Miles Davis, and
From The Beginning, from the album
Trilogy (2015 Remastered), by Emerson, Lake & Palmer, to make the comparison. Each song was of the same selection from Qobuz. Equalizer was set to "flat" for all listening.
Streamer: WiiM Pro Plus
Preamp: McIntosh C27
Poweramp: McIntosh MC 7150
Speakers: Hales Audio System II Signature Series
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I listened to each song several times, alternating between the AirPlay feed and the Wi-Fi feed, and listening to specific sections of each track for comparison. In each track I found the Wi-Fi feed to have more air to the sound. Both the AirPlay and the Wi-Fi were crisp and clean, and gave spatial awareness. Where I heard a difference was in the "presence". The AirPlay sounded just slightly muffled, and definitely as though it was being heard through a stereo system. The Wi-Fi, on the other hand provided a more realistic sound; as though I was sitting in front of the performers.
I'm not an audiophile reviewer so my assessment may not have all the correct terminology; it's just my description of how I interpreted the music.