How far can the sound of the Rally system speakers project?
The Rally speakers are ultra-low distortion designed specifically for speech and enhanced echo canceling. When the system is used in an application that enables a microphone (such as video conferencing and recording applications), the speaker output is binaural/double mono. When used in applications with no microphone input, the speaker’s output stereo.
Theoretically, if the room is 35' long, the standard delta will be ~27 dB SPL between the front and the back of the room. It’s roughly the difference between a car engine revving right next to a listener (~100 dB) and somebody talking in a slightly raised voice (~75 dB) next to the same listener. So one should consider how loud the front of the room needs to be to fill the space. There may be situations where the speakers may fill the space but create an uncomfortably high volume for participants who sit closer to the speakers. In a case like this, it would be better not to use the Rally Plus system but a full 3rd party system (with mics and speakers) and the Stand-Alone Rally Camera.
(Example calculation results at 35' away from a Rally speaker playing at full power (7.5W) are found at this link)