How many singing competition shows can America watch each week? That’s the question being asked now that NBC’s “The Voice” has started its second season with a bang, while Fox’s long-running “American Idol” has seen its ratings decline. “It’s still very early on for ‘The Voice,' but they got a great start coming out of the Super Bowl with 37.6 million viewers,” media analyst Brad Adgate of Horizon Media told Fox411.com. “The most watched ‘American Idol’ was the finale between Clay Aiken and Ruben Studdard in 2003, with a little over 38 million viewers.”