Sound Pressure Level decreases by 6dB for every doubling of distance from the source loudspeaker. This means that 96dB at 5m from a loudspeaker will reduce to 90dB at 10m - a significant drop in energy.
Because of this level drop over distance, in larger rooms it's worth considering additional loudspeakers to counter this effect, maintaining volume and intelligibility. In this case, it is important that the second row of loudspeakers down the room are delayed to match the arrival of the sound from the first pair of speakers, as shown below.
Loudspeaker delay can be set from within WebApp. See WebApp - Line and Amplifier Output Processing