A particularly interesting question that presents an idea of “sound purity” – as if anything else that is separate from the sound being displayed/played is not a part of the music/piece itself. The first thing I think of when presented with this question is a crowd in a concert and whether the noise of the crowd creates a certain bias – or even friction – towards the music. In my opinion, it is based upon the intention of the music being created. There are whole genres based upon the liveliness of the crowd the music is being shown to – Dance music for example is created with a certain rhythm and BPM to be played in a certain environment (e.g a club) for people to – as the name suggests – dance too, thus creating an environment where the audiences interaction with the music is a vital part of the listening experience. On the opposite side according to the Academy of Movement and Music “Whistling, yelling, or otherwise congratulating the performers is generally not appropriate for classical music concerts.”
http://www.academyofmovementandmusic.com/music/concert-etiquette/
This shows that different pieces are intended for different environmental situations. The intention behind what the artist has created requires certain type of external sounds which may or may not be controllable by the artist. for example the idea of Joao Gilberto threatening audience members if they coughed too much during a show goes to show how much it matters as a subject. If artists cannot control the external effects that could potentially ‘tarnish’ their music how much artistic control do they truly have in terms of presenting their music?
The average listener – when listening to music – will tend to block out sounds they don’t pay attention to and so in this way it is extremely subjective. Is the amount someone pays attention to the piece itself what creates the impact of artistic expression?