The digital music landscape is littered with the corpses of startups that tried and failed to offer free music downloads. One of them was Qtrax, which imploded amid controversy and lawsuits a few years ago.

Now Qtrax is back from the dead and — according to its founders — back on track. But what makes them think they can succeed this time?

“What we’re doing is, without question, overly ambitious,” said Allan Klepfisz, an Australian entrepreneur who, along with Lance Ford, a former British rock musician, is restarting Qtrax to much skepticism. Critics point to false starts and missteps in the company’s history and say its plan to make a profit solely through advertising is untenable.

Qtrax’s ambitions may seem quixotic, but it does offer something distinct in the current market: free and legal music downloads.

Klepfisz says he isn’t trying to compete directly with Internet radio stations like Pandora, Slacker, turntable.fm, iHeartRadio and Radical FM, or with Apple’s iTunes store for paying customers. Instead, he is aiming at the millions of people who now go to pirating sites and other outlets to download songs illegally.

About 95 percent of music downloads in 2010 were unlicensed and illegal, with no money flowing back to artists, songwriters or record producers, according to Alex Jacob, a spokesman for the International Federation of the Phonographic Industry. So riches could await a company that persuades some of these Internet scofflaws to change their ways.

Illegal downloading does have drawbacks that go beyond the threat of prosecution, which is relatively rare among average listeners. For one, the sound quality can be poor. For another, the songs on illegal sites can harbor viruses.

Good news for people who love bad news

Qtrax says it offers free, high-quality and safe downloads, now on laptops and coming soon to mobile phones. Unlike streaming services, which need a strong Internet connection and often require subscription fees, Qtrax listeners can tune in to their music where there is no Internet — on subways, say, or in that log cabin deep in the wilderness.

But there’s a catch. The Qtrax music can be played only on a Qtrax software player, which is free but must be downloaded — ads included — from the company’s website.

Klepfisz and Ford first introduced their baby in January 2008 in Cannes, France, with a multimillion-dollar splash at Midem, one of the music industry’s most prestigious trade shows. They rented suites at the Intercontinental Carlton hotel, in anticipation of a flood of news media requests. They also sponsored lunches at the conference hall and hired LL Cool J, Don Henley and James Blunt to rock out at a private party, and the buzz was on.

They boasted of big-name advertisers, including Ford Motor and Burger King, and said they had the blessing of the major record labels, along with some 25 million tracks available for download.

But within days, one of the major labels announced that no licensing deal had been signed. Trade show attendees soon learned that formal licensing agreements had not been signed with any of the four major labels, that the depth of advertising support was exaggerated, and that the number of available tracks was highly questionable.

The backlash broadsided Klepfisz. “We took a massive reputation hit,” he said.

Klepfisz says he and Ford were simply naive and did not intentionally mislead anyone. On the wall of their 28th-floor office in Midtown Manhattan is a sign that reads “naive” in big block letters, given to Klepfisz by his former wife, Jennifer, as a commentary on Qtrax, he says. (She had to suffer through its first start, he notes.)

He says talks had been under way with the four labels, and that he was led to believe that they supported the venture even though formal agreements had not been hammered out.

Klepfisz says he now has official, short-term licensing agreements with three of the four major labels — Sony, EMI and Universal. For confidentiality reasons, he declined to give details about the cost or the length of the licensing pacts. As for the claim about offering 25 million tracks, he acknowledges that he jumped the gun, saying that it was the number he estimated the company could eventually offer as the licensing agreements were rolled out.

Sony and EMI confirmed that short-term agreements with Qtrax were now in place but declined to comment further. Universal did not return calls, and negotiations are still under way to get a licensing deal with Warner, the fourth major label. Klepfisz says all of the licensing deals will need to be renewed this year, but adds that he’s confident they will be.

He says 2.5 million tracks are available for download, with plans to offer at least 5 million and possibly 10 million by year’s end. (Most digital music subscription sites worth their salt these days have 10 million or more songs available in their libraries, says Aram Sinnreich, a media professor at Rutgers and a co-founder of Radar Research.)

If you got your money, honey

To shore up their financial position, he and Ford have been focusing on fundraising. In 2008, when venture capital, private equity and hedge fund markets dried up during the economic crisis, they had to start looking elsewhere for cash — mostly in Asia. Klepfisz says the company has raised “tens of millions of dollars,” with about 20 percent of that coming since the restart.

Still, Qtrax is relying primarily on the ads linked to the music player to finance licensing fees and to make the company profitable — a business model that many industry experts are skeptical can work. They point to previous hopefuls like Napster, which was sued by the record labels over copyright laws and is now a shadow of its former self (and now charges subscription fees for music) and to SpiralFrog and Ruckus, which had some backing from the major labels but collapsed after failing to raise enough cash to cover royalties to the record companies.

Even Pandora is struggling to turn a profit, and it gets revenue from both ads and subscriptions, said Mark Harding, a digital media analyst at the Maxim Group. Pandora offers free Internet radio, but it charges a subscription fee for those whose listening exceeds 40 hours a month. And Pandora’s licensing fees for streaming are far lower than those of companies that offer downloads.

Qtrax uses banner ads on the player that downloads and plays the music. Ads are also found on pages on the site that provide information about the bands. Users see three ads a page when they download or play a song — but the ads do not delay or interfere with the ability to download or listen, Klepfisz says.

“We are diametrically opposed to placing ads that precede listening to the music — that forces people to endure the ads before they can hear the song,” he said. “We think that if you do those sorts of things, people will go back to the illegal sites.”

Qtrax executives feel strongly that artists deserve to be paid for their work. “Every time something gets played, they deserve to be paid something,” Ford says. “They’re getting paid nothing now for most of their music. Zero.”

He adds that Qtrax goes far beyond SpiralFrog in terms of licensing deals and content. And Qtrax is enhancing its site with band information, live performances and ticket sales. The site will get a cut from those sales, and from merchandise sold through site links, he says.

It is also aggressively seeking partnerships like those it has with Baidu, the Chinese search engine, and with Lenco Media, which supplies Internet radio stations with technology and advertising. Under these agreements, people searching for a particular song through the Baidu search tool or listening to a song on an Internet radio station through Lenco’s platform will see a button that allows them to download the music from the Qtrax site.

Klepfisz does not rule out offering a subscription service, streaming or even a cloud service at some point, but says he feels that offering free downloads is crucial to luring music fans away from illegal downloading sites.

“For the moment,” he said, “we want to start with tackling the pirate industry.”