While you cannot "download" 3D capability for hardware that doesn't support it, you can download content specifically mixed for spatial listening:
Research platforms like ResearchGate often host technical papers and accompanying audio samples of new 3D rendering models. skachat 3d zvuk
Traditional 7.1 surround sound is limited to fixed speaker channels. Spatial audio is dynamic and can often be experienced with just a standard pair of headphones. While you cannot "download" 3D capability for hardware
To get the most out of your downloads, you may need to enable spatial processing on your operating system: skachat 3d zvuk