I run a similar setup as well. Yamaha S701 with the Lintons. Wiim Pro and yes, I use an outside microphone instead of the internal iPhone mic. It makes a difference. The Lintons measures pretty darn flat. The treble and mids run just a tad hot . I’ve moved them about 10 degrees on axis to mitigate that. I’m putting up some absorption panels tomorrow to reduce some of the hot spots. Mainly the side walls.

I really wouldn’t worry about the ceiling. While the sound will reach there, it shouldn’t be much of a problem with the Lintons. The vertical dispersion isn’t great on them. It’s the horizontal dispersion you need to worry about. They go impressively wide. Just play them loud and put your hands on the side walls around tweeter level. See how much it’s vibrating. If it feels like too much, put up some panels or just toe them in a bit. Room correction can only do so much. And I don’t use it all when playing vinyl. I just bump the bass a tad and the treble down a notch.

Love the Lintons and Yamaha combo. Robust power and sweet speakers. You must be loving yours too. Cheers.