'Reshade' for sound?

Maybe a dumb question but are there any apps out there that almost act as a 'reshade' for sound? It would be awesome if you could really craft audio in any game more - like manipulate reverb settings of sounds (separate from music), may increase the # of channels or simultaneous sound effects etc. I know of apps like Boom 3D of course, which can be good but I also don't like that they behave as virtual sound cards since most good headphones have built-in sound cards so they conflict when trying to use both. (I use Hyper X Orbit)

There are plenty of sound processing software for pc, APO Equalizer for example, but nothing exactly what you're suggesting for. In fact, it is impossible because games do not output their sounds using different channels or tracks per audio type. They output audio in different channels according to your audio system, ie. stereo or different 3d audio formats. With those, you can do editing per channel but nothing else.

TLDR; No. You can only directly mod the game's audio files.

There is an HRTF sound mod for X3DAudio games github.com/kosumosu/x3daudio1_7_hrtf
that makes sounds 3D per sound in-game.

Same type of stuff for OpenAL games blueripplesound.com/gaming blueripplesound.com/products/rapture-3d-user
The OpenAL Soft is a free alternative to Rapture3D openal-soft.org

So I guess it would be possible to make programable sound.

Wow, interesting, thanks! Exactly the kinds of things I was looking for...back in the day I was blown away by games like when Doom 3 implemented EAX HD. (of course if you had a Sound Blaster card) The difference was awesome. The 3D audio of most games is pretty underwhelming so I'm looking for ways to try and tweak outside of the usual apps like Razer THX, Boom3D etc.

The problem with using any software that modifies audio in real time is that it adds latency -- so the sounds will noticeably lag behind the action in games.

Our ears are _really_ good at picking up on stuff like that, unfortunately.  IMO if you want higher quality sounds, get a decent audio card that has a decent DAC and some really good closed or semi-open or full adjustable over the ear headphones (probably german-made).