Earnings season is back upon us, and one of the most anticipated earnings conference calls has got to be Apple’s. The company announced its next investor call today on its investor website : Tuesday April 23, at 2 p.m. Pacific time. Revenue will definitely be down from the company’s traditionally big holiday quarter, but the big question will be how Apple’s Q2 2013 will compare to Q2 2012. With two product lines — iPhone and iPad — making up 72 percent of Apple sales, Apple’s quarter — and its sagging stock price — will hang on those two products. But the limited amount of data we’ve seen lately on iPhone and iPad sales has not been great. Apple lost some U.S. smartphone market share this past quarter, and with some analysts saying that iPad shipments collapsed in the first month of this year, it’s likely we’ll see minimal growth at best. To make matters worse, it looks like Apple’s best-selling iPad model is the cheaper, lower- margin iPad Mini , meaning that even with good unit sales, revenue and margin could be problems. Investors at Estimize are projecting revenues of $ 43.5 billion, up slightly from the year-ago quarter of $39.2 billion, but the Wall Street consensus is only $42.5 billion. In early 2012, when Apple stock was in the middle of its incredible growth phase, its Q2 numbers were down 15 percent from the holiday Q1. This year, if Apple hits the Street consensus, it will be down 22 percent from first- quarter numbers. Either direction, this quarter will be one that confirms the nay-sayers’ opinion that Apple is slumping , or if the company can pull some magic with a spectacular quarter, one that reaffirms the believers . Apple stock is down almost $14 dollars today to $ 428.91. At its height in October 2012, Apple stock hit $702.