What we hear comprises:
- direct sound; that which arrives directly to our ears from the source
- late-arriving sound; that which is reflected from various room surfaces before arriving at our ears
Reflected sound can either support or detract from the listener’s understanding of speech. One of the key factors in designing rooms to support speech is how long the reflections take to reach the listener. It is important to be aware that:
- early reflections (<30 milliseconds) of sound largely assist with understanding
- late arriving sound or reflections that arrive as an echo can detract from our ability to comprehend speech
Learning spaces designed in consultation with an acoustic consultant will often contain specific areas designed to reflect sound (to support speech) and areas which primarily absorb sound to control reverberation.
For critical listening spaces such as tiered lecture theatres or performance spaces the geometry of the space also plays a critical role in the acoustic performance of the space. Therefore early input from the project acoustic consultant is advisable when planning these spaces.