Posted by in part... on November 06, 2003 at 13:25:03:
In Reply to: Practice-room sound posted by SHS Tubamaster on November 05, 2003 at 21:00:31:
...it is the result of relationship between the wavelength(s) of the tones being produced and the dimensions of the room.
See an acoustics book for (some) discussion of standing waves which will exist between the three sets of parallel walls and also the diagonal corners of the room.
Then there is always practicing out-of-doors...NO reinforcement there!