i have always felt some unexplained effect while listening to Veridis Quo [1]. the melody start sounding different from the 0:38 mark, just as the kicks come

i have always felt some unexplained effect while listening to Veridis Quo [1]. the melody start sounding different from the 0:38 mark, just as the kicks come in. it seems like some supporting keys are added with the kicks, to make the sound more full, but at the same time it could be my brain getting tricked. sorry for botching the explanation, i have never studied music. [1]: https://www.youtube.com/watch?v=TCd6PfxOy0Y https://www.youtube.com/watch?v=TCd6PfxOy0Y