From Devialet Tech Support: How Phantom, Dialog & Wifi Router communicate

[Taucher669]

In case you use Spark via Dialog, no matter if mp3, aac or flac - all content is send in bursts from your source to Dialog and music files are cached in Phantoms. In case Airplay ist used - files are really streamed in realtime over the network to either Dialog (2. Gen) or Gold Phantoms. Only 1 device in the whole setup must have the Airplay chip, either Dialog or Phantoms.

Interesting thing - I run 2 Golds, 1 Silver (no Airplay) in the same room via a 1. Gen. Dialog (no Airplay) but Airplay still works on all 3 Phantoms. It seems that in case of Airplay my Golds are distributing the stream back via Dialog to my Silver Phantom.
Even more interesting: I use with this configuration Tidal MQA via Airplay and it works with the full bandwidth. Sound via the Tidal Desktop App (Mac) is amazing - a huge differenze compared with Tidal in FLAC/HIFI mode on Spark. I have compared several Albums and MQA result appears to be much more clear at high end, more controlled and clean at low end, better stage. Try Phil Collins Face Value (Remastered) or Pink Floyds The Division Bell (Remastered)