Room acoustics

The acoustics of a room is generally linked to a term which describes the room's actual acoustic properties in relation to the use of the room. The general perception is that it is the room's reverberation time which theoretically can be calculated or measured on spot which is essential for how one perceives a single room's acoustics. This is not always right as in many instances other terms can be used like for e.g. speech intelligibility, which can be measured with the aid of STI (Speech Transmission Index) or RASTI (RApid Speech Transmission Index).

Speech intelligibility can be simply described as how clearly information from the
sender can be heard/recognised by the receiver.

If a large room's reverberation time is reduced because of an absorbent enclosure and the room is used for e.g. teaching, meetings, conferences or similar, there can be problems with understanding the information a sender passes on to a receiver.
This phenomenon can be described by rating with RASTI values.

Perforated plaster products, which are a combination of absorption (holes) and
reflection (the smooth plastered areas), will in many cases provide good speech
intelligibility.