Common, Billy Joel, Maroon 5 and 122 other musicians rallied on Wednesday against Pandora's plan to slash artists' pay when their songs are played over internet radio.

In an open letter that will appear in Billboard magazine this weekend, the consortium of artists praise the online radio service, saying they're "big fans," but questioned why the company would cut pay to musicians when its revenue is growing.

"That's not fair and that's not how partners work together," the letter says.

Internet radio companies, such as Pandora, are pushing Congress to pass the “Internet Radio Fairness Act,” which could slash by 85 percent royalties paid to musicians and artists when their songs are played on such services.

“These artists have joined together to tell Pandora it’s time to go back to the drawing board.  We all want Internet radio to succeed, but it won’t if it tries to do so on the backs of hard working musicians and singers,” Ted Kalo, the executive director of the musicians' advocacy group musicFIRST, said in a statement.  

In September, Pandora founder Tim Westergren sent a letter to users saying the disparity between digital radio companies' royalties was drastic, and the congressional bill could correct that to make it fair.

"This bipartisan bill will correct the incredible inequity in how different digital radio formats are treated under the law when it comes to setting royalties," he wrote. "The difference is extraordinary."

According to his letter, Pandora paid more than 50 percent of its revenues to artists, while SiriusXM paid less than 10 percent in 2011.

"As a lifelong musician, I'm fully supportive of artist compensation, but this situation can't continue," Westergren wrote. "Internet radio is bringing millions of listeners back to music, and is playing the songs of tens of thousands of promising artists who would otherwise never be heard. It should be given a fair chance to succeed."