Starting September 1st, Pandora users will be able to listen to as much free music as they want. The streaming radio company has just announced that they are planning on lifting the 40-hour per month cap on free mobile listening that they instituted earlier this year.

That move was something that Pandora called very unusual, and something contrary to their mission.

“We’re pleased to once again maximize free listening for everyone on Pandora,” said Tim Westergren, Pandora’s founder. “The more than 70 million listeners that tune in every month will now have more time to hear the music they love, and thousands of working artists will reach more fans.”

When Pandora instituted the 40-hour per month cap back in February, they cited rising per-track royalty rates, which were up 25% over the last 3 years. This time, they are citing “rapid progress in mobile advertising” as the reason they are able to lift the limit.

It’s unlikely that the listening cap, and now this uncap, will affect that many Pandora users. The company claims that less than 4% of their users even hit this 40-hour limit. The average Pandora user streams about 20 hours of music per month.

Pandora just posted its Q2 earnings, announcing record revenues of $162 million – up 58% year-over-year. During the quarter, users streamed over 3.88 billion hours of music.

[Image via Facebook]