I think it comes down to subtle mathematical properties of the sounds.

Many years ago there was an article in Scientific American that talked about how most art depicts something from the world but music doesn’t really sound like anything in nature, not even birdsong. So what does it sound like? It turns out that all popular music, regardless of genre, predominately features fractal patterns, and so does our nervous system. If you measure nerve activity at the periphery like on your skin you get a lot of white noise, and as you probe closer to the central nervous system the signal gets more fractal - as if our nervous system itself is built to filter out the white noise and let the fractal components of our perceptions through. So presumably fractal patterns play a part in our processing and maybe how we do pattern matching. In addition, if you measure the difference between moving patterns in nature - like trees waving in the wind, or people moving around in a crowd, the difference between one moment and another is strongly fractal. In other words, fractal patterns could be important in how we perceive changes in the world around us.

This could explain why specific pieces of music can almost universally sound happy or sad, or stirring, or comforting, or can remind us of a specific person or experience - even if it’s a song we’ve never heard before. Anyway, my guess is that if you did the right math on metal and folk music you would see a lot of similar numbers.