There are numerous so called "VST-plugin" effects available on the internet.
These VST effects can be used to manipulate audio.
I would like to know if there's a way to use the VST plugins with the .NET framework.
Yes there is! https://github.com/obiwanjacobi/vst.net
It supports implementing plugins in a .NET langauge that will run in unmanaged/native hosts (DAW) as well as hosting (loading) unmanaged/native plugins in a .NET application.
Marc (author of VST.NET)