Since the OP asked for their mind to be changed.... I will be oppositional. Is there any height to width ratio for a room where you would say the ceiling is not the most important surface to treat?
I could think of other exceptions, but while they might fit the letter of this thread, they certainly would not be in the spirit.
I have never thought about the relative effects of sidewall versus ceiling first reflections. Now I wish I had an empty room, so I could compare untreated to sidewall first reflection only to ceiling first reflection only.
i had this on my mind few no days ago in live video i mentioned " cloud " and real ones and ceiling height
i think i look at loft if had stepladder to get up there and multi mics , length and width so i can sine pink noise RTA test how much bass is up there and how to reduce it even if small amount or think of way of using it to improve bass ? what ever ,
otherwise i think diy the cloud is cheaper , wood and rockwool or maybe layers of MFD screwed to the ceiling with a sandwich of other parts between it
i be sizing up rockwool to sort a small bass snag out , been on my mind for , no years now won't be cheap but if it even improves and alter raises narrow part of bass freq , fine i have MDF cut size and finish off behind the screen make it , cat proof one my cats , ' Bear ' likes going behind projection screen , not good if playing THX sound system , it damage his hearing
i test rockwool and use mic where no mic has gone before , to get the data results if possible on REW ,
i guess i need x6 packets to do 18" thick , sigh i have to make it so dense and then cut size MDF and then cover MDF with some of that treatment fabric i have , cover so it won't have bare reflect mid high sounds or sound like reflective narrow echo or pinging sound , it should fill in where that small narrow bass dip is and raise it up , rather than Eq-ing which doesn't help it , reduces dynamic amp headroom
as for floating suspended MDF rockwool clouds it get in the way of the video projector light beam , good idea if my ceiling was any higher , but i look outside at night i see an infinity amount that expands back into the expanding universe at day i see clouds or scattered clouds with blue atmosphere some 60 miles above where the air gets dense cold and sound slows down , that's my understanding of clouds , just vapour
i would test speakers outside and place these clouds suspended above with REW results , then again i can use large sheet of cardboard hold it above me , yes i hear oddness in part of the sound pressure like sounds like a surface boundary above me !
i want see ASR members do more videos of show me your clouds , pink sine noise mics placed above and below cloud and see here some results for entertainment science