Numark this week will introduce the iDJ2, a new version of the company’s professional iPod mixing console. Unlike the original iDJ, the new iDJ2 features only one iPod dock, but can play two songs simultaneously from a single iPod. The mixer provides real-time scratch, pitch control, looping, and full cueing of music from the docked iPod. Numark said iDJ2 owners can also use USB devices such as ha