General Motors Concerts, offering classical music on the radio, were heard in different formats on the NBC Red and NBC Blue networks between 1929 and 1937. The concerts began 1929-31 as a 30-minute series on the Red Network with Frank Black as the musical conductor on Mondays at 9:30pm. It also aired as General Motors Family Party. The 1935–37 Red series, expanding to a full hour on Sundays at 10 p.m., featured Ernö Rapée conducting, along with violinists Yehudi Menuhin and Erica Morini, tenor Lauritz Melchior, and sopranos Kirsten Flagstad, Lotte Lehmann and Florence Easton.