Without getting all technical here's a (very) brief explanation of the main four categories of beat, known as binaural soundwaves, and the effects they can induce. Effects are obviously dependent on the listener choosing to relax and focus on the rhythms.
Intention is the key factor in any meditation or visualisation exercise.
The varying levels of trance state happen by beat, meaning how many beats there are per minute, and the pitch of the sound. They are:
TRANSLATED TO FAMILIAR NOISE
High sounds and fast beats to me resemble clattering rain or standing close to a waterfall – a huge gush of sound I find overwhelming. This is known as white noise.
High pitched sounds do not personally help me relax, though I see how they clear the mind of chatter simply by drowning the eardrums in noise. In beats terms this would be Beta, a frantic sound that awakens, heightens the concentration.
My choice of track (and beat) is an intuitive choice dependent on frame of mind. I am conscious some make me more at ease, and others induce a higher imaginative state so I am selective. For instance, Alpha is useful but light; the midway point. In Alpha I find I’m not able to get lost in my imagination which is needed for proper visualisation, but it can be restful.
Theta is steadying in that I find I’m locked into the repetition, like being grounded; it is solid and reliable. At times it can also be too invigorating, heavy or binding.
Finally, with Delta the beats are further apart, almost indistinguishable. Barely beats as such but waves of sound that reverberate; they wash over you. Delta is lulling, soothing, gentle, like steady chant from a buddhist temple; the resonance of Himalayan singing bowls. It is a ‘beat’ that hangs; a chime; a sound that clings to the moment and allows you to cling back and sink into it.
I will divulge some of my personal go-to tracks and soundscapes in a future post.