Crystal Mixer is based on OpenAL engine surround sound mixer. It supports up to 8 direct output and input channels and up to 18 output channels through 3D mixer. It works through ASIO Driver API for versatility. Possible to use up to 15 customizable auxiliary effects. It is also possible Hardware acceleration with some sound cards.
As player foobar2000 recommended (create custom channel mapping in ASIO panel), you can also use plugin foo_dsp_fsurround (https://hydrogenaud.io/index.php/topic...