@spenav
Thanks for reporting back on the fruits of your labour! Must admit I like the look of the diffusing panels.
I've now had a virtual look at your system and see you already have everything you need for 'immersive' sound, except possibly silver disks for the source!
I know you believe that for 'solid' sound, two channels are necessary and sufficient. I argue that two channels are necessary but not necessarily sufficient.
So can I suggest another experiment for you to report back on, which is even less expensive. Just pop an "immersive" disk (multi-channel SACD or Blu-Ray) into your Oppo and let your Marantz processor use all its channels as it thinks best. Preferably connect them via an Ethernet-capable HDMI cable.
Many of the recordings from Norwegian label 2l.no ship with hybrid SACD and Blu-Ray containing an assortment of hi-res formats. I've suggested Reflections which is classical but there are many Grammy nominations in their catalogue.
Love to get your reactions .