Analysts expect Apple (AAPL) - Get Report to post its third consecutive quarter of declining iPhone sales volumes when it releases quarterly earnings after the closing bell on Tuesday. "I think [Apple CEO Tim Cook] is going to point to very strong growth in the services business, such as Apple Music," said Michael Ingram, a market analyst with BGC Partners in London. In its fiscal third quarter, Apple services revenue rose 19% year-over-year to roughly $5.98 billion, while iPhone and Mac revenue fell 23% and 13%, respectively. Ignram also comments on Alphabet's (GOOGL) - Get Report new Pixel phone. TheStreet's Scott Gamm reports from Wall Street.