Known good room ratios. Ceiling height?

I seem to recall reading , but cant remember where, that the recommended ratio's we see bandied around here are based on the 1 being a 10ft. ceiling. If you were to use a 8ft ceiling, as in my case, do the formula's now become void? Do they still apply but would be more effective if you had a 10ft. ceiling? Or does it not matter in the slightest and Im imagining some sort of issue that dosent exist? Thanks.

The ratios still apply: they are RATIOS, after all! Yes, originally some of them assumed 10 foot ceilings, and some of the testing was done in such rooms. But that doesn't make the equations invalid for other heights: they still apply, but with a caveat: always check the actual modal response for all modes (axial, tangential, and oblique), since there can be surprises lurking in unexpected places! As a general rule of thumb, the lower the ceiling and smaller the room, the more likely it is that the room will have problematic modal behavior. So the full answer is "yes and no": Yes, the ratios still apply for other ceiling heights. No, a single ratio cannot tell you the whole story about a room: you need to look at the actual modal spread to be sure. - Stuart -