After reading this article I thought long and hard about what exactly is noise. And where are the boundaries of music or art? For some people, a sound that is not pleasant to listen to is considered noise, or a sound that exceeds normal sound levels is considered noise. But some of these so-called noises can become pleasant when they are rationalised.
For music or art, it seems to me to be a relatively free dimension, some people say that music has to be melodic or played with instruments. But it is not. Music or art is supposed to be another form of expression besides speech, and there is no definition or very specific theory to cover it.