If people are close to the holograms (IE within 1m), only one person can see them effectively at one time. Other people can still see the hologram but it will appear to bend slightly. This is likely to occur when closely inspecting museum artefacts, hologram food from a menu, or other single-object displays.
Alternatively, if your audience are more than 3m away you can have up to 30 viewers. An example of this will be large scale presentations or scans, where the hologram wall functions more like a window to the outside world.
Holographic Tours can also take up to 30 viewers, however all viewers must be more than 3m from the device.