Dan231,
Here is a excerpt from a conference phone guide, I can't remember which one, that will explain why there could be some echo.
Each conference room will have unique acoustical characteristics; the room’s acoustical characteristics can be affected by a number of different factors such as room dimensions, floor coverings, wall coverings, ceiling construction, furniture and the number of occupants.
In most cases a room’s dimensions cannot be altered. As a result, the only way to modify a room’s acoustical properties is through the use of different building or decorating materials. In general, rooms can be grouped into three different acoustical categories: neutral, too live or too dead.
In a room that is acoustically too live, sounds will echo or reverberate. This is due to there being too many surfaces in the room that reflect sound waves. Items that will reflect sound waves are typically hard flat surfaces such as, tiled floors and hardwood floors, glass walls and windows, ceramic walls, and dry-walled ceilings.
In a room that is too acoustically dead, sounds will seem to disappear or be absorbed by the room. This is due fact that there are not enough reflective surfaces in the room. Items that will absorb sound waves are typically soft materials and irregular surfaces such as carpeted floors, curtains and draperies, venetian blinds, upholstered furniture and people.
A room that has neutral acoustical characteristics will provide the most natural sounding environment since sounds waves will not be excessively reflected or absorbed.
Thanks,
TE
