Back in the '70s, music radio entered a whole new era with the rise of the FM band, which offered much clearer and better sound than AM. You could hear the voices and the drums but now you could also hear the violins and the voice of the backup singers.

Across the country, stations jumped over from AM, and new ones sprouted up. Ever since, there’s been a simple division of labor for radio; FM stations played music, AM stations aired talk.

But that’s changing. Now FM is seeing a surge in talk.

In just the last 14 months, some 50 FM stations have reportedly switched over to some sort of news or news/talk format. At the same time, there’s been a growing number of FM stations airing sports talk.

The reason is pretty clear. Besides the better sound, FM offers a significantly larger and younger audience than can be found on the AM band.

Why now, one might ask. Why not 10 years ago, or 20?

Part of it has to do with a mindset. Call it the AM talk, FM music paradigm.

“The belief that FM is just for music and AM is just for talk is a myth that has only lived in the heads of radio executives,” says Jim Farley, vice president of news/talk programming for Bonneville Broadcasting.

Says Eric Johnson, program director of WKXW/Trenton, one of the first FM-talk stations in the country: “The 25-54-year-olds listening to radio now grew up with top 40 or rock on FM. AM is something their grandfather listens to.”

But the bigger part, what’s driving the rise of FM talk, is money.

In many cases, owners of struggling FM stations are moving to talk because the format can be much less expensive to operate. They can take advantage of an abundance of successful syndicated talk shows that are available at no cost while getting out of having to pay music licensing fees, which are on the rise.

A big player in the rise of FM has been the Talk Radio Network (TRN), which syndicates many well-known talk hosts including Michael Savage, Laura Ingraham and Mancow. The company has been aggressively identifying ailing FM stations and selling them on the idea of switching over to talk.

“Every market has one or two struggling FM music stations,” says Phil Boyce, TRN’s president of programming. “Now instead of becoming the third country or AC station, they can be the first FM talk station.”

But in addition to cutting costs, FM stations switching to talk gain an advantage they likely never had airing music. That’s a unique identity in the minds of listeners.

If you are a music station, you may be one of dozens in a market, and it’s a real struggle to set yourself apart. That struggle has only become harder with the rise of internet radio.

But if you are talk, you have a real identity through unique proprietary content that competitors simply can’t duplicate. You’ve got Ingraham or Mancow, and your listeners are tuning in to hear them. You’ve become their station.

With that sort of engagement, listeners are more likely to stick around during commercials to hear what comes next.

Plus, since the programming is all talk, the spots don’t seem nearly as disruptive to the listener.

“Ads on our FM talk stations have become less strident, less loud,” says Farley. “They tend to include more information, which is why the listener came to the station in the first place.”