absorption cunfusion!?

hello, i was trying to figure out reverb time of a room but i m stuck at some points.. does the "stud" affect RT60?? i mean, are the absorption coefficients of "gyprock" and "gyprock on stud frame" different?? and also, do "double glazed glass" and "normal glass" have same absorption coefficent? i couldn't find anything about this on coefficient charts.. does anyone know these absorption coefficients? cheers, ilter (edit) one more question: let's say that all walls are splayed.. does this mean there are no resonant frequencies at all in that room??