Thanks Mtrycrafts. Your comment had me totally baffled because you say that the opposite of what I wrote is in fact the case
. After re-reading your words though, I think we are actually in agreement!
. Can you confirm?:
The way I picture things in my mind's eye, low frequency waves would travel right through the door's mass as if it didn't exist in the first place, so that whether the door is or is not there, there is no difference (as may be seen from the applicable plots).
However, since higher frequency waves won't travel through the door's mass, it does make a difference whether the door is there or not because in one case (the door is there), the waves will be reflected, and in the other (the door is not there), they continue on out into the hall.
Isn't this true?