I’ll be frank with you: “Active rock” is a rather awkward-sounding phrase, one that reeks of a radio programmer’s desperate attempt to will into existence a new demographic of rock fan. But while you, me and my Aunt Louise all can bemoan such seemingly dubious marketing ploys, it doesn’t mean the concept behind the phrase is bunk. Quite the opposite, in fact. What active rock attempts to define is the all too fluid yet very real commercial zone that exists between classic rock and alternative rock. Granted, it’s a zone that didn’t necessarily exist before the rise of grunge in the mid-’90s. However, by reconciling ’70s rock hooks and punk-inspired grittiness, Pearl Jam, Soundgarden and Alice in Chains uprooted the signs and signifiers that traditionally distinguished fans of underground rock from their more mainstream-oriented counterparts. In the process, they fundamentally altered the pop landscape.

Since those heady days, the number of big-time rock acts that rightly can be labeled as “too alt-sounding for classic rock radio, yet too classic-sounding for alt-rock radio” has increased 100-fold, easily. The most obvious examples are, of course, those heavyweights of the still-sprawling grunge diaspora, everybody from Foo Fighters to Stone Temple Pilots to 3 Doors Down. But active rock also cobbles together a slew of high-profile artists with roots in subgenres as diverse as Brit rock (Radiohead, Muse, Coldplay), alt metal (Stone Sour, Incubus), indie rock (Arcade Fire, Imagine Dragons, The Killers), nü metal (Linkin Park, Fiver Finger Death Punch) and garage rock (The White Stripes, The Black Keys, Kings of Leon). It also encompasses those first-generation alternative acts that through the decades have transformed themselves into global icons: U2, R.E.M. and the Red Hot Chili Peppers. Though our Evolution of Active Rock playlist only scratches the surface of the format’s ever-growing catalog, hopefully it will further your understanding of what it is I’m yapping about. — Chuck Eddy