One challenge with audio in conference rooms is acoustics. The acoustics of the room greatly affects the audio performance in the room. This is particularly important when there is a large portion of speech, such as in video and audio conferencing. When the room is being designed from an architectural perspective, the acoustics should be considered depending on the usage of the room.
While acoustic treatment can be implemented in an existing room, the best result is always when the room itself is designed and built with the acoustics being taking into consideration. This also enables a more integrated solution, with some aspects not even noticed by the users of the room.
A good overview of room acoustics can be seen in a video produced by Production Audio Video Technology. Click on the below image for the 5 minute video.