The controversy surrounding next Tuesday’s vote at the FCC on white spaces is heating up as bigger names enter the debate. The regulatory agency will vote on whether to open the unused spectrum for auction, however there’s continued debate about the potential for interference with adjacent airwaves. Because of that, the issue has set up a battle between broadcasters and technology companies that want the airwaves for new wireless devices. FCC Chair Kevin Martin has long had a plan to improve broadband penetration in the U.S. and his current proposal would more likely make that a reality. If passed, the winning bidder would be required to set aside a quarter of the network’s capacity for free broadband, which would be subject to filtering.

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To put some fresh collective heft behind their opposition to the plan, more than 100 recording artists sent a letter to the regulatory agency that outlined their concerns, Reuters reports. The group told the FCC that unlicensed white space use would “dramatically impair” their ability to perform live with the aid of wireless microphones. “The thought of having to debate each night which band member gets to have the one wireless microphone that might be available in a given market on a given night is not a scenario we want to face, nor is it one that benefits the concert-going public,” the Recording Artists Coalition wrote. Dolly Parton also wrote directly to the FCC asking for more time to review: “The importance of clear, consistent wireless microphone technology cannot be overstated.” Echoing opposition from others, the American Federation of Television and Radio Artists also weighed in to urge a delay.

In the other corner, Google (NSDQ: GOOG), Motorola (NYSE: MOT) and Microsoft (NSDQ: MSFT) have all voiced support for the plan, heralding it as a once-in-a-decade opportunity to reach more users through unlicensed access to broadband. Microsoft founder Bill Gates has already lobbied Martin and Commissioner Michael Copps to support the plan and stepped up his efforts this week in a chat with Commissioner Robert McDowell. With Washington well into lame-duck season, the Nov. 4 vote could very likely fall down political lines with support from the Republican majority. AFTRA’s letter (PDF).