I've always received the notion of "acoustic space" with a skeptical attitude. It's my standard knee-jerk disposition toward any notion coeval with the vacuous pop art concepts of the 1960s and 1970s.
But I've warmed up to the concept now that I'm more acquainted with the work of Marshall McLuhan (1911-1980), an eccentric man with many wrong ideas and many brilliant ones, who popularized the phrase.
I've also been forced to acknowledge its relevance by the repeated and abrupt trespasses of my endlessly-ringing telephone–especially as punctuated by telemarketers. The telephone has forced me to feel the existence of acoustic space.
Indeed, the very existence and popularity of Caller ID gives support to the notion of acoustic space. Caller ID, after all, is a guard and a guard implies the existence of a space to be protected.