Randy Yates wrote:
inside surface of a 1-inch-thigh steel wall (part of a strange listening

I meant to write "1-inch-thick".

room); then we moved 1.5 inches in and measured at (x+x0, y+y0, z+zo).
The frequency response would then drastically change for just a small change
in position, even for low frequencies. No?

The point is, even though a vector sum of low frequency waves
doesn't change much when moving through a small fraction of
a wavelength, might you not still get a big variation when
moving through a small fraction of a wavelength if, during
that movement, the system response changed at that frequency
due to the position-dependent spatial properties of the room?
--
% Randy Yates % "...the answer lies within your soul
%% Fuquay-Varina, NC % 'cause no one knows which side
%%% 919-577-9882 % the coin will fall."
%%%% % 'Big Wheels', *Out of the Blue*, ELO
http://home.earthlink.net/~yatescr