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Pink Noise Reflection

The first 4 seconds are the sound of pink noise coming from a single speaker to the listening position in the AVRS Surround Sound Acoustics Lab with all first order reflections absorbed. The last four seconds are with gypsum board placed over the first order reflection point of the near sidewall so that it can reflect. Note how much change occurs to the timbre of the pink noise with this single added reflection.

 

Each speaker sends sound directly to the listener. This is the shortest distance and the first to arrive at the listener. The speaker will also send sound out to the rest of the room to be reflected back to the listener later in time. Each speaker will have a first order reflection off each wall, floor and ceiling. Thatís six reflections arriving behind the direct sound for each speaker. In a 5.1 system, thatís 30 first order reflections. If left untreated, these reflections will continue on to become second, third, etc. order reflections. These non-direct signals distort the original signal by introducing time, frequency and energy anomalies. These are perceived as shifts in image location and tonality, and also cause poor articulation, dynamics and resolution. In a controlled environment, these first order reflections would be controlled by designed absorption and/or diffusion (see Frequency Response Panel (FRP).

Note, this monaural recording of a single reflection reveals tonal changes, but cannot reveal spatial changes.

Click Here To Hear The Sound Clip

 

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