I advise watching all three parts to the video but listen specifically to where he explains how to get the relationship between kick and bass working together. One Point of note is that if you are inputting a lot of sub frequency information and tuning things.......essentially what you are doing is lining up sine waves and stacking them on top of each other. Your ear doesn't hear separate sine waves at low octaves, you are basically stacking sine waves which can lead to phase issues. He explains why you only really need one fundamental at any one given time.
The whole video series is well worth a watch, you will learn more about mixing in these three videos than reading through endless pages on forums:
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