Pandora recently announced plans to introduce a 40 hour listening limit for customers using the service on a mobile device. The steaming music outfit says the new restriction will not affect most users as less than four percent of their total monthly active listeners surpass this mark.

The blog post points out that limiting listening is a very unusual thing to do and contrary to their mission so they at least wanted to share an explanation. The company explains that their per-track royalty rates have increased more than 25 percent over the past three years which includes a nine percent hike already this year.

Pandora co-founder Tim Westergren forecasts an additional 16 percent surge in royalty rates over the next two years. He said that after a close look at their overall listening, the 40-hour mobile listening limit allowed them to manage the rising costs with minimal listener disruption.

In the event that a listener does hit the mobile limit, there are a couple of options to keep the tunes going.

Users can elect to pay $0.99 to enable unlimited streaming on mobile for the remainder of the month. There's also the option to sign up for Pandora One which provides commercial-free unlimited listening. A full year subscription will set you back $36. Finally, if you aren't interested in shelling out any extra dough, you can always switch to a desktop or notebook and enjoy unlimited streaming until the next month rolls around and your streaming hours reset.