Audio power amplifiers (APA's) share a number of PCB layout requirements. Class-D APA's offer far better efficiency than class-AB, and they achieve this with switching outputs. As a result they have some additional layout requirements. These include placement and routing of power decoupling circuits and EMC filters.
WIth the right presentation these requirements are easy to understand, so that an engineer is equipped to do a correct design. The attached training presentation, IC Audio Power Amplifiers: PCB Layout for Audio Quality, EMC and Thermal Success (Home Entertainment Devices), provides the information a design engineer needs to succeed.