Sculpted foam panels, or panels that have a convolution (pattern) cut into their face, expose more of the pores of the foam to air space, increasing the panels ability to capture and convert more sound wave reflections out of a space. Flat foam has a lower overall surface area, presenting fewer pores to the same air space. For intents and purposes, sculpted foams, such as the Pyramids, VCuts and Wedge patterns, will out perform flat foam when it comes to capturing echoes and lowering sound levels.
That being said, sculpted foams can vary in their ability to control echoes in a room. Much of the effect that you get from convoluted foam panels depends on how deep into the face of the panel the convolute is cut. A 3″ thick Pyramid foam panel with a 2.5″ cut into the face will leave just .5″ of base to the foam, while the same 3″ thick Pyramid foam panel with a 2.0″ cut into the face will leave a full 1.0″ of base to the foam. The thinner the base to the foam, the worse your results.
Word to the wise when buying sculpted foam. Ask your supplier what the base thickness is and choose wisely!