Just looked up the Sony UBP-X800 connectivity. Since it has a dedicated HDMI for audio, and another one for video, could I theoretically send the audio only to my "old" HD-HD621, and separately send a 4K video signal directly to - say - a 4 K projector, without the need to upgrade to the new UHD722?

Jerome
Music: NUC + ROCK + QObuz > MS600 > G65 > DSP8000SE + DSP5200HC.SL + DSP5200SE rears
Movies: Apple TV > HD621 > G65 > DSP8000SE + DSP5200HC.SL + DSP5200SE rears