Commercial 100V ceiling speaker packages are complete kits for music, announcements and voice alerts in busy environments and medium-large public indoor areas. Use higher power for larger areas or louder environments and extend using add-on packages if more speakers are needed. As an example, a 3m ceiling height needs approximately 5m spacing between speakers, so 4 speakers could serve a 10 x 10m square room. For higher ceilings, the spacing can be widened but the 8" speaker models are better equipped to deliver sound to the listener at a distance. RM-series mixer-amps have a Bluetooth receiver, mp3, FM tuner and are specified in each package based on the maximum speaker Wattage tappings. It is recommended to tap down the power of some perimeter speakers so that the total combined speaker Watts is <90% the amplifier max output power. Using lower tappings on more speakers can allow additional speakers to be added to the line, again observing the <90% rule.