You may have heard it when flipping on a light, switching on your TV or walking near power lines — that unmistakable hum of electricity. But what, exactly, is that hum? And more important, is it ever ...

What’s your favorite bedtime jam? Do you doze off to jazz, a babbling brook, a crackling fire or a whirling fan of white noise? Or maybe you’re a sound aficionado, and have replaced your white noise ...