This study considers the role of the distributor effect during the bubble generation, growth and interaction within a bubbling fluidized bed. To characterize this effect, short-term and long-term dynamics are explored in time and frequency domains. Controversy occurs when inspecting what is actually known of the gas distribution mechanism in bubbling fluidized beds. To sustain discussion, classical and innovative techniques, such as Digital Image Analysis, DIA, and Wavelet Analysis WA, are used. As a result, the conclusion is that the distributor not only has no effect in the averaged long-term dynamics but also has no effect on the general bubble generation characteristic frequencies. The analysis performed on the bubble generation region concludes that the distributor design has a great influence at the short-term scale such as during the bubble generation process controlling the spatial distribution of the bubble nucleation sites over the distributor plate. (C) 2018 Elsevier Ltd. All rights reserved.