As has been said by many, frequencies can model unseen realities that inhabit the same space just like the radio waves from all the stations can (invisibly) coexist in the same space. This is due to the wavelike nature of matter termed deBroglie waves. But as normally presented it is too hand-waving and it leave several questions unanswered. For instance, why doesn't things easily pop into/ visibility if all it take is to tune in/out of specific bandwidth?
Remember that I had attempted to answer this by invorking some 'law' that demands that equal amount of the seen must go to the unseen as the amount of the useen comming to the seen. Combining this to the frequency idea, it states that for frequency of anything to step up from a lower frequency, another thing must step down from an higher frequency. We will then see that this is due to a very natural conservative law.