Honk if you’ve heard this one

And they say Los Angeles has no respect for the past.

KNX-AM’s distinctive call -- several horn-like beeps that fade in, then out, and repeat -- has survived to honk another day.

Broadcast since the first Nixon administration, the radio signature is the city’s oldest “sounder” at the city’s oldest station.But several months ago, the seconds-long traffic alert was on the block as KNX (1070) prepared to move from its historic Columbia Square broadcast center to new studios on Wilshire Boulevard’s Miracle Mile. Executives commissioned new sound introductions for all the station’s news, sports and roadway reports.

But in the end, executives balked at replacing its venerable traffic trademark.

“It’s the only sounder that didn’t change and won’t,” said KNX’s Vice President David G. Hall. “We all grew up listening to it.”

This was just its latest reprieve; over the years, the sounder has survived multiple station retoolings, revampings and overhauls in format, management and location. Conservative estimates say it has aired more than 2 million times in nearly four decades.

In contrast to its longevity, KNX’s sound was developed in less time than it takes to navigate the 5 Freeway from downtown L.A. to Orange County during rush hour. In 1969, the station had recently converted to a strictly news format and needed a clever, but quick, way to highlight its new emphasis on delivering traffic reports.

Fred Bergendorff, the station’s then-promotions director, volunteered for the creative task. The musician and songwriter had conjured up other sounders during his radio career and wanted to take a crack at this one. He retired to a sound room and began “poking around” on a Moog synthesizer, an electronic keyboard. In about an hour, he had what he thought was the right combination of notes.

“I wanted it to sound like a car horn,” said the 61-year-old Escondido resident. “But it has an unusual feel, a unique trailing-off effect. Every time it fades, it plays again.”

“When you hear it, you don’t even have to think,” he added. “You just know a traffic report is on the way.”

Although it mimics a car horn, it doesn’t sound exactly like one -- a good thing for the durability of Bergendorff’s invention.

(Other radio stations have fielded numerous complaints for airing actual car horns. “Suddenly, I heard a burst of horn-blowing, and I immediately freaked out, thinking there was a vehicle in my blind spot ready to squash me like a bug,” wrote Gretl Collins of Atlanta to NPR’s ombudsman a couple of years ago. “By the time I recovered just seconds later, I realized the horns were on the radio show. Joke’s on me, huh?”)

When KNX General Manager George Nicholaw heard the sounder, he instantly knew it struck the appropriate chords.

“Sometimes you make changes in radio to move with the times, sometimes you are ahead of the times,” Nicholaw said. “And other times you manage to stay ahead of them for decades. That’s what Fred did.”

Little did either know that the traffic sounder would stand the test of time. Today, it airs every 10 minutes on KNX, but for more than a decade of its run, it played every six minutes.

Radio historians say its long life on L.A. radio puts it among an aged and elite group of sounders. For certain, there is at least one more famous and older than KNX’s: that of the NBC chimes.

The simple three musical notes -- G, E, C -- first were broadcast in the 1920s, typically at the top and the bottom of each hour via NBC radio networks, and did so for over half a century.

Today, of course, the chimes live on as an instant identifier of NBC, though on its television networks.

“Sounders probably owe their heritage to the big bands,” said Chuck Schaden, a radio historian based in the Chicago area. “Each one had a theme song, whether it was Tommy Dorsey or Glenn Miller. When you heard it, you’d sit up and take notice.”

The NBC chimes were the first audio trademark to be registered with the U.S. Patent Office, in 1950, according to a network spokeswoman. (The KNX sound was not registered.)

For Bergendorff, now host of cable television’s “The Pet Place,” which seeks to provide homes for stray and rescued animals, the traffic alert was part of the job and, unfortunately, doesn’t garner residuals every time it airs.

“I’d be a multimillionaire by now if I got paid every time the needle dropped,” Bergendorff said.