Crowley, Aleister - from Yoga for Yahoos - Mantra yoga
Type of Spiritual Experience
This technique was used by Aleister Crowley in his system of Magic. In Crowley’s system it was used alongside a number of other complementary techniques.
He implies the rhythm - the beating sounds too
A description of the experience
From Yoga for Yahoos
I should like to add a few words on the subject of Mantra-Yoga, …. In Book IV., Part I., I have described it, with examples, quite fully enough. I need here only say that its constant use, day and night, without a moment's cessation, is probably as useful a method as one could find of preparing the current of thought for the assumption of a rhythmical form, and rhythm is the great cure for irregularity.
Once it is established, no interference will prevent it. Its own natural tendency is to slow down, like a pendulum, until time stops, and the sequence of impressions which constitutes our intellectual apprehensions of the universe is replaced by that form of consciousness (or unconsciousness, if you prefer it, not that either would give the slightest idea of what is meant) which is without condition of any kind, and therefore represents in perfection the consummation of Yoga.