Ts (Centre Time)

Centre Time (Ts) is the time at which the centre of gravity of the squared impulse response occurs, representing the balance point between early and late energy in the room’s temporal response. Defined in ISO 3382-1:2009 §4.5, Ts provides a single-value characterization of the early-to-late energy ratio without requiring an arbitrary time boundary (as C50/C80 do). Lower Ts values indicate clearer, more definition-rich sound, while higher values indicate a more reverberant quality. Ts correlates well with subjective clarity judgments and is considered a more robust metric than C80 because it does not depend on a fixed integration limit. Typical values range from 60 ms (very clear, dry room) to 250 ms (highly reverberant concert hall). Ts is useful in room acoustic simulation and design because it provides continuous, position-dependent feedback on the early-late energy balance without the step-function behavior of clarity metrics at the integration boundary.