It may be hard to believe, but it’s been under four years since the Amazon Echo was first introduced in late 2014. Since then, the number of companies offering or developing so-called “smart speakers” has mushroomed to the point where smart speakers have become yawningly commonplace. The recently introduced Sonos Beam, though, takes the concept of a smart speaker to an entirely new level—and into a previously neglected room. When Beam begins shipping on July 17 of this year, it will include Amazon Alexa as a built-in voice-control service; and, Sonos says, Beam will have…