By STEPHEN KINZER
Todd Buchanan for The New York Times
Bill and Sonia Florian have sold WNIB-FM, a classical music station in Chicago, for $165 million. CHICAGO — For nearly half a century, lovers of classical music in the Chicago area have been turning to WNIB-FM (97.1) for eclectic and sometimes obscure programming. They hear live broadcasts of the Cleveland and the San Francisco Symphony Orchestras, interviews with contemporary composers and even, on April Fools' Day, broadcasts of a work by John Cage that consists of 4 minutes 33 seconds of silence.
Occasionally the barking of one of three dogs that make the studio their home can be heard in the background while announcers cue up Bryn Terfel or Martha Argerich.
This mix of fine music and down-home warmth has been the station's trademark since it began broadcasting in 1955. It is still run by the same couple who started it, Bill and Sonia Florian, who virtually live in the studio and have made the station an extension of their own quirky preferences and personalities.
But the station's long run as a beacon of classical music in the Midwest is apparently ending. The Florians, both now approaching 70, have sold it for $165 million to an out-of-town company that is expected to switch its format to pop music.
"We do it with a lot of regret," Ms. Florian said. "Radio has changed so much in the 45 years since we started, and it's going to change more with satellite and Internet radio. It's becoming more of a business and much less a labor of love, which it was for us for a very long time. When you combine that with the price that was being offered and our sense that there's going to be a recession, we decided we should do it now."
When the Florians bought their station, the FM band was just beginning to fill up, and stations could be purchased cheaply. They paid $8,000 for theirs.
Later they bought a smaller station that transmits from north of Chicago, WNIZ-FM, a deal that allowed them to cover a larger area including southern Wisconsin. Both stations, which now simulcast to a total of about 350,000 listeners, are included in the sale package.
Prices for stations began rising steadily after the late 1950's, but they took a sharp jump after Congress amended the Federal Telecommunications Act in 1996 to ease restrictions on the number of stations that a single company may own. The couple turned down several offers in recent years but were finally persuaded to sell when they received the $165 million offer from Bonneville International Corporation of Salt Lake City, a company affiliated with the Mormon Church. Bonneville already owns 18 stations across the country, including three in Chicago.
The price is one of the the highest ever paid for a radio station in Chicago. Bruce Reese, Bonneville's president, said media companies like his competed intensely for the few stations that come onto the market.
"This is a good business with a nice margin, and it's in a period of consolidation," Mr. Reese said. "Americans are still in love with their cars, and radio is the medium of choice there.
The new law gives companies like ours a chance to develop some scale."
Mr. Reese said his company had hired market researchers who are working speedily to determine what kind of format to program on WNIB. He said he would announce his choice after the Federal Communications Commission gave what was expected to be routine approval to the sale, probably in the next few weeks.
Although Mr. Reese said he had not ruled out keeping the station's programming, industry analysts said that format would not be nearly as lucrative as more popular ones. Bonneville owns one classic rock and two adult-contemporary stations in Chicago.
The demise of classical music on WNIB would reflect a nationwide trend. By one count, the number of commercial stations in the United States that offer mainly classical music has dropped to 37 today from 52 a decade ago. There are also slightly more than 100 nonprofit stations with classical formats.
In another reflection of this trend, the only commercial radio station broadcasting mainly classical music in Denver, KVOD, was recently sold. Its classical broadcasts ceased on Dec. 31.
Chicago is one of the few cities with two classical music stations. The second, WFMT-FM, is expected to continue with that format.
"Deregulation revolutionized radio and made the value of stations really astronomical," said Kal Rudman, who publishes a group of radio industry trade journals. "Now, with companies able to buy as many stations as they want, it's becoming very difficult for niche music like classical to survive."
"This certainly isn't a good trend for classical music in general, because when any kind of music disappears from the airwaves, that's more or less the end of it," Mr. Rudman said. "National spot advertisers want to target the age group from 25 to 54, and the classical audience is heavy with the over-55 group. It shows you again that this business is not about music. It's about advertising."
Mrs. Florian said she and her husband planned to use most of their newfound wealth to establish a foundation that would provide money "for the arts, for animals and for preserving habitats."
On a recent morning she sat at the station where she and her husband have spent nearly every day of their adult lives, looking at a brochure advertising a world tour of remote places. The stops include Katmandu, Ulan Bator, Vientiane and the ancient ruins of Petra, Samarkand and Angkor Wat.
"I've been hearing the names of those places all my life," she said.
"They're faraway and exotic, and that's what I'm looking for now."