In places like train stations, metro stations and airports, PA systems are essential because there is always the need of announcing departures and last-minute changes. Although very important, the intelligibility of these systems are usually very low due to the low quality speakers in extremely reverberant rooms.
All examples with auralization are marked with the icon . In order to have an optimal performance when listening to the audios, please use headphones (better than e.g. stereo or surround sound system). You can read more about auralizations, openGL and measurements vs. simulations at this page.