The Reverberation Time is defined as that time span within which the Sound Pressure Level of the Steady State Sound Field decreases by 60 dB after the sound source has been switched off. The so-called Early Decay Time (EDT) T10 is taken as measure for the 'Reverberation Time' in CARA. The 'EDT' is defined as six times the time interval for a 10 dB decrease of the 'Sound Pressure Level'.

The 'EDT T10' is determined from the Reverberation Diagram being calculated in CARACALC.

The frequency dependence of the 'EDT T10' is determined from additional 'Reverberation Diagrams' which are calculated for 40 separate frequency bands (see curve 'CARA-T10' in the diagram).

The 'Reverberation Times' determined by the well known formulae from Sabine, Eyring, and Kuttruff are displayed as well in this diagram. Matching of these 'Reverberation Times' with reality is sufficiently well, if the respective rooms are rectangular or at least convex.

The EDT 'CARA-T10' values matches with reality, if the room acoustic calculations have been carried out with a very high degree of accuracy, which requires the parameter Maximum Reflection Order to be set to about 20.