The resonance time (Rt) in a particular room is the time sound takes to fade away when striking one wall, bouncing across to another surface and so on. If the resonance time is long because of acoustically lively hard surfaces the sound can build until speech and audio are indistinct. The level and character of noise in enclosed spaces is affected by room dimensions and the sound reflective characteristics of boundary surfaces.  This reflected sound effectively adds distortion and the addition of reverberant noise increases overall sound levels. Significant reduction in noise can be achieved with careful selection and positioning of sound absorbtion materials.