Shape and Spread

[Ben B]

These parameters, as they are implemeneted in Lexicon processors, are some of the most useful things to me in achieving the sound I want. I describe their effect as that of a "density envelope," wherein shape determines the overall contour of the density changes over time, and the spread determines the duration over which these changes occur. (Note this is not the same as RT60.)

Does anyone know specifically how these same reverberant qualities would be affected by acoustical factors indoors? What would you need to do to a room to raise or lower its "shape" (in the Lexicon sense) or "spread?"

My inital guess is this: The equivalent of high shape (in order for it to be discernable) would only be possible in a reasonably large space, which is either not rectangular, or has many large reflective surfaces within. Spread might be a function of how large that space is, plus the amount of sound energy being directed into the room in the first place.

Can anyone correct me, or add to this?

Thanks very much,
-Ben B