In this work, single channel source separation with empirical mode decomposition method is considered. Zero crossings of the signals decomposed into intrinsic mode functions with empirical mode decomposition are investigated using various number of sources. For this purpose, source mixtures with various mixing ratios have been used both for samples having single frequency components and samples of music and speech signals. Results demonstrate that zero crossings are cumulated at first intrinsic mode functions but distributed similarly in different modes.