This is not "music" (please, no one get angry at me or insulted because I am calling this "music"!), but I found it interesting the way they have arranged the NASHEED in an orchestral manner, and it seems to fall into the category of "halal":
Prohibitions are based on hadith. Interpretations of Islamic law which allow for use of musical instruments are based on reconsidering the applicability/correctness of those hadith or the cultural context.
For instance, the type of music that is mentioned in hadith was usually associated with licentious behaviour, alcohol, dancing slave girls, and other ethically problematic things, whereas elevator music does not have those connotations today. Still, it is good to consider that certain instruments may have positive or negative effects on people ethically or spiritually, and not to assume that everything is cultural context - God knows best.