Making music for CS

[Kurton]

Horror music is a really nuanced sort of genre, but also really flexible as when composing say ambient music you have some more freedom to go crazy with tone and harmony, intentionally forming dissonant or ugly-sounding chords. On the other hand it takes a lot of fine-tuning, especially if you follow the style of Amnesia where every sound is based on real instruments and not synths, and without practice it's tricky to get something that sounds believable.

One Creative Commons site you could visit is Jamendo.com, there is an immense catalog of music from all genres and I'm sure if you poked around for specifically horror or dark ambient you'll probably find something to strike your fancy.

A digital orchestra is typically a sample-based software component you can use in a swath of music programs such as Ableton, Logic, etc. They're a pretty penny from what I've seen.