I’m not trying to be argumentative here, but this concept really doesn’t make any sense to me. For me, how comprehensible the Dhamma being taught is to the audience at hand is of paramount importance, not the method in which it is delivered.
I say this because I listened to countless desanas as a monk and as a layman and, while I felt that they were beneficial, I never felt like I had made significant progress until I discovered Pure Dhamma and read about concepts like san, gandhabba, the difference between bhava and jati, the true meaning of Tilakkhana, dukkha and all of the etymological break downs of Pali words and their relationship to the Sinhala language. The clarity and understanding I felt from reading about these things was immediate and intense, far greater than anything I’d experienced from listening.
Could the fact that I was ordained during the time I absorbed all of this information be another factor to consider? How significant of a role would it play in accelerating one’s progress and also, is it possible to bypass that need to physically hear a sound to attain magga phala if one is absorbing Dhamma while one is ordained?