cowhorn
Welcome! There are a few fans and owners of Model CS 2.3 speakers. Good move by replacing the Denon AvR. Your room is quite large. It could be a case of the front end not providing enough head-room? A pair of CS 3.7 loudspeakers would flourish in a room that size. Something to consider if you continue to enjoy Thiel Audio sound. I look forward in reading more developments.
Happy Listening!