To add to Tam's and Ivan's comments, considerations such as providing the required level to all listeners, and perhaps not to where you don't want it, should be the driving force behind selecting the speaker(s). Without knowing the potential speaker locations, the areas to be covered and so on, there is not much basis for any specific recommendation.
If they just want something to make sound and don't care if it can actually be heard or understood, then one speaker is probably as good as another, it may end up replaced soon anyways when they decide they do actually want everyone to hear and understand what is being said.