"Ethan Winer" ethanw at ethanwiner dot com wrote:

thus making the tiny room "look" bigger aurally? Not a bad idea, really.


This is true for all absorption. For example, putting absorbers on the
ceiling over a drum set makes the ceiling appear to be much higher. If you
think about it, there's no difference between a ceiling that's fully
absorbent and one that's infinitely high. Either way, sound that goes up
does not come back down later as a reflection.

Here's something that's puzzled me, Ethan. I've read that when calculating
modes, etc, for a room with an acoustic ceiling, you should measure the
height to the actual hard surface above the acoustic tiles. It makes sense
that as you APPROACH full absorption, you would APPROACH infinite effective
height (i.e. zero reflection). But in practice, these are only
approachable limits, not actually attainable, right? Whouldn't any low
frequencies that are not fully absorbed be reflected in the same timeframe
as if the absorption was not there? Or does the absorption affect phase as
well as amplitude?