Sonic Emotions

ALEXA HAS NO knack for pianissimo. Here's how to tell. Set her to living-room volume and ask her to play Berlioz's rapturous epic of sex and opioids: Symphonie Fantastique. The opening passages should be erotic and feather-light, but on the Echo the massive orchestra comes through as smothered whooshes, the exhalations of a pint-sized table fan caked in…