Two possibilites to increase the effect of binaural beats I collected references, supporting the hypothesis that binaural beats have an influence in our brain (see here). 

I currently see two possibilities to possibly increase the (measurable) effect of binaural beats:


What-ever brain wave doesn't have a fixed frequency but a range. Sweeping across the frequency band could be an improvement.
Sweeping the volume from left to right.


Is this already researched?

EDIT 2: Sometimes (white, pink, brown) noise is mentioned to increase the effect. There might be a optimal signal-to-noise ratio...

EDIT: The frequency of the sweep shall be low. My focus lies on hitting your personal resonance frequency to increase the effect of binaural beats. As written in the linked post: This maximum declines as the 
carrier moves away from 440 Hz.
Both of your proposed methods to increase the measureable affect of binaural beats on the brain would introduce a monaural beat. For example, sweeping the volume from left to right means the volume in at least one ear is changing over time. You would hear a beating if you listened to just this ear. Similarly, to sweep the frequency range, you would need to change the frequency in at least one ear. If you listened to just this ear, you would hear a "beat" (or more precisely frequency modulation). 

I am not aware of any research on how sounds that have both monaural and binaural beats affect the brain. My guess is that people who are interested in using binaural beats to influence the brain would stay away from stimuli that have monaural beats since you can hear the monaural beat with a single ear. From my understanding of the literature on using binaural beats to influence the brain, there is something special about binaural beats since the beat is created by the brain (which is sort of true and sort of wrong).