I really appreciate that, Adam. Did you recallibrate afterwards? I wonder if your centre speaker was less efficient or whatever it might just have sent what was already set for that channel to the front pair? On my amp if I switch the centre out it doesn't let me control the level of the centre channel in the amp settings, so I assume it either locks out what was already set or ideally ignores previous EQ, distance, & level settings and just lets the front pair setting deal with it. That said, I'm still running a centre channel at the moment and it's not all tracks on the Atmos Automatic that I have an issue with for vocal levels/sitting in the mix. I'm wondering if there's some kind of dynamic compression issue that's not working together with other channels or maybe some kind of reverb thing on the vocals in the mix alongside the level that's not always working for me.
so sorry i somehow missed your post all this time!!
i think the lower level Centre vs higher level when rerouted to Front L&R thing may be to do with taking content designed for one speaker and when it gets redirected into two speakers having greater power and volume than one centre speaker you get those Centre channel elements plus any replication of Centre channel content already mixed into the original Front L&R more prominent in the mix?
i'm sure somebody more technical can explain it with statistics, diagrams and so on!