Speaker height vs ceiling height

get 7 foot 1 inch speakers, then you can use them to support the ceiling...dual purpose

Why people bother to waste time posting when they have nothing useful to share? Worse when they are cynical about a perfectly genuine question

Ihcho,
I believe if speakers is too near to ceiling , it's similar to placing speakers too near to sidewall. There are a lot of software to help u to check out room mode issues with such close placement to ceiling

Take a joke.
Having said that there are tall speakers that beam in narrow fashion like a Electrostat so there is no easy answer. There is a huge difference in how a Planar, Electrostat and a Dynamic behaves.

Ihcho,
There is no exact answer, If the speakers had an ever so slight tilt downward, you might get away with 5 ft to 5 1/2 ft, but in general I agree with Audioblazer. A boundry must be considered. Again, in general I would say 4 1/2 foot max. Depending on dispersion patterns of the speaker you choose and even how far your seating position is and how loud you listen, this could change.

Height is not nearly as big of factor as length and width are. For someone to say you could not put a 6ft speaker in a 7ft tall room is making a way to blanket statement. IMO.