As alisson said, We know the limitations about fmod license, but comparing with other HRTF capable engines was the more friendli compare with others.
Two other options that I've considered was openal, and slab3d. The last have a very impressive results, but have problems with one shot sounds because was designed to be used as an sound scene dessigner with multiple looping streams working on it, or similar; but if you want to simulate various sounds while you are rendering a scene is very hard to handle this. And openal... well, sounds very good, but it only supports raw pcm streams and you have to use other layouts first to decode sound formats, and fmod can handle all of these things directly. For now fmod directly lack of HRTF, but you can implement it using the plugins of oculus, resonance audio, or steam audio.
But well. ABout c# I love the languaje, works fine, have a good performance ( I know that isn't the best so far) and for owr purposes is OK. If you preffer c++ or other stuff like rust, take your pill and well. Because that we have a lot of good languages that can handle all of these good things.
So! If some one knows a good openal Wrapper for c# Or another sound engine working over openal for c# I'm happi to ear you :3, because more options more fun.
A, I know that monogame can use openal for some platforms, but you can't modify directly the properties of the openal used with the engine; someone of audiogames got enable HRTF in monogame, modifing the source of the project and passing the corresponding config flags at the openal initialization time, but as I know, for now monogame don't give to you the option to enable it directly configuring your engine :3
sooo. that its.
pd: irrklang... O, irrklang I love that library; is so sad that it not been updated a lot of time ago; and I asked to the developer about HRTF, but... for now aparentli don't have interest on update the librari to support it.
About bass... Well, I don't know really much about bass; I know that it don't support HRTF for now, but well.
bye