Tidal vs ATC

That is a very big room to deal with.....Keep in mind that the Tidals will be a clear lens for everything that comes before them. Imo, that means that your amps and source will need to be of very high quality. An amp that will be required to fill that room will be costly....If you want to spend the dough on the required source and amplification ( and cables ) to match the resolution of the Tidals then you will have a stunning system. 
On the other hand, a pair of big, active ATC's with a great source may be more cost effective...In either case, a forum like this one will be of little help at this level of investment- you need a good dealer and in home demo imho. Good luck!  

Ok thanks guys. Ill just try to find a place to demo ATC.
As for Tidal I was thinking of pairing them with tidal electronics or Pass XS line.

Never heard the ATC, but if I were in that market, Tidal is where I'd look first. I heard them at the CA Audio Show last summer; I think the model was Contriva G2, powered with Bricasti. It was the best sound of the show by far for me.

A big thumbs up on the Contriva G2, 3 1/2 years of ownership and still frequently miraculous!

Have heard both. Am very familiar with the Tidal speakers and have spoken at length with Jorn Janczak. They really are two different animals. Tidal gear in general is beyond over engineered and can literally handle anything you can throw at it. There is no input signal it can’t accurately reproduce at almost any volume.