How to Set Up Videoconferencing Camera and Audio
Tips on Placing Audiovisual Devices for Best Picture & Sound
May 26, 2009
Video Conferencing covers a huge range of systems and technologies, but they can broadly be split into systems that are designed for business use such as those made by Tandberg, Polycom, Radvison and Cisco, and those that are designed for domestic users.
The latter use covers applications for use with webcams like Skype and Windows Messenger, perhaps to keep in touch with family members. However, there are some things that are common to both types of systems.
Lighting for Video Conferencing
Just as in photography, lighting should come from behind the camera, not in front of it. That lighting should also be diffused rather than from point sources. Strip lights or lamps with large diffusing lampshades are good - creating soft shadows rather than harsh and high-contrast images.
For instance Cisco's Telepresence 500 all-in-one terminal includes its own striplight above the screen. Windows should be behind that camera rather than in front of it. This is all too often violated, particularly in office desktop systems where the user is sitting with a window behind, making for a dingy image as the camera tires to expose for the outside rather than the participant inside.
The participant should appear as a medium close-up head and shoulders image, since video conferencing systems are not particularly detailed, and the background should ideally be a flat evenly illuminated wall in pastel shades rather than any really strong colour.
Provided the camera can zoom and the screen showing the other end is large enough, the camera and screen should be a couple of metres away (about 6ft). Conventionally the camera is placed above the screen, it should be as close to the top of the screen as possible.
This reduces foreshortening of the subjects, so their nose does not appear excessively large like in so many webcam shots. The far end gets a better experience with the participant appearing to look them more in the eye as there is less of an angle between the video camera and where most participants look, which is where the eyes of the far end are on the display screen.
Sound for Video Conferencing
It is the sound channel that carries most of the information between people communicating, and yet this is all too often the Achilles heel of video conferencing installations. The principle is reasonably simple - the microphone should be closer to the talker and the loudspeaker further away. They should never be on the same surface.
In most rooms it is best if the microphone is within 50cm (under 2ft) of the talker, and the loudspeaker should be quite a bit further way, at least twice the distance away as the furthest talker. Low-end systems for the domestic market do not handle sound particularly well at all, and these benefit greatly from the use of a headset with boom microphone.
These eliminate spillover from the far end talking feeding back to the microphone, which is something that low end videoconferencing systems cope with poorly; if even one of two participants uses a headset the intelligibility can be improved no end.
Professional systems often come with a boundary microphone which is designed to be placed on a large flat surface like a meeting table. These favour sounds from above the flat surface so the loudspeakers should never be placed on the same table, which will make the echo cancellation work harder and reduce intelligibility. Once again the near end talkers should be closer to the microphone than the loudspeakers are.
Related Article
Introduction to Video Conferencing
