When you have an instrument, say a Harp which produces varied frequency vibrations by plucking the strings, each individual string resonates at a specific frequency, or tone. Same as with piano, or tuning fork. As any musician will tell you, regular preventative maintenance is required if you wish for the resonance to be pure, and true. If left unattended for long duration, a layer of dust will accumulate, becoming stronger with time, until at last it is more akin to rust. Without being cleaned first, this string will not resonate true and pure...but instead will have a discernible, discordant distortion to the sound. This distortion becomes critical when we stop to consider that we're going to base our choices and decisions on what we think the universe is showing us. Kind of makes a good case for zero distortion reception, which is probably not even attainable in this here and now, probably more of an evolutionary goal.
full article here