Texture refers to the time structure of the pattern in which the reflections reach the listener. The first reflection should quickly follow the direct sound to achieve intimacy , which successive reflections following quickly thereafter. To achieve good texture, it is generally necessary to have at least five reflections within 60 ms after arrival of the direct sound. An important related requirement is that the overall sum of the reflected waves combined should on the average decrease uniformly in intensity. The structure of the hall should not create any single unusually large echo or have a tendency to focus sound; otherwise, poor texture may result.