You need to plan your sounds. Just like graphics, sounds are an important part of the experience for the user. As I have stated before, you need a good modeler and visual artist in your team if you want to create compelling experiences. The same goes for sound; you need to have effects that are used well. Now, it is hard to find people who can advise you on that. The gaming industry figured this out long ago, but for most developers, this is all new. Add to that the capabilities of HoloLens, and you will understand why we need to spend some serious time on this topic.
We need to discuss some general principles that come into play when we want to use spatial sound in our applications. These design principles should be firmly locked in your brain, as they apply all the time, in every single app you will write for this platform.