It is interesting that the site mentions drones, noise, fuzz and walls of reverb as being conducive to concentration. I tried a number of these tracks, and these were the features that caused me to abandon a track. Dissonance would probably aso have that affect, but ambient music tends to avoid it.

Softly-spoken words in a language I do not understand seem to work.

It may be that I am just selecting for sounds that I can ignore. When I really need to concentrate I, like the OP of this thread, prefer silence, though, unlike the OP, I am not musically knowledgeable.