Superior audio for Windows PCs is anything but a straightforward process, requiring deep knowledge in a number of otherwise unrelated areas. The complete signal path requires collaboration between motherboard designers, BIOS programmers, industrial designers, driver developers, DSP engineers, software application engineers, and system designers. Optimal Sound is the only independent provider of insight into the entire audio ecosystem. Using a combination of APOs, filter drivers, customized INF files, and HLK DTM Testing, we can provide complete customized logoed audio driver packages which leverage and extend the Microsoft-supplied UAA HD Audio and USB Audio class drivers.