NEW YORK (Billboard) - 50 Cent's new album, "Curtis," has been pushed back another week, from September 4 to September 11, according to Interscope, which declined to give a reason for the move.

"Curtis" originally was slated for a June 26 release but was pushed back in late May.

Two singles from the project have met with little success on radio. "Amusement Park" peaked at No. 36 on Billboard's Hot R&B/Hip-Hop Songs chart and is No. 57 in its ninth week there, while "Straight to the Bank" peaked at No. 30 and has since fallen off the chart.

Another new song, "I Get Money," debuted in early July at No. 75.

"Curtis," which is the follow-up to 2005's "The Massacre," features production from Dr. Dre, Eminem and Timbaland, plus guest turns by Eminem, Akon, Justin Timberlake, Mary J. Blige, Robin Thicke and Nicole Scherzinger from the Pussycat Dolls.