Welcome to the fourth volume of Game Audio Programming: Principles and Practices – the first series of its kind dedicated to the art, science, and craft of game audio programming. This volume contains 17 chapters from some of the top game audio programmers in the industry and dives into subjects that apply to diverse game genres and from low-level topics such as thread-safe command buffers and pitch detection to high-level topics such as object management, music systems, and audio tools. With such a wide variety of topics, game audio programmers of all levels will find something for them in this book. The techniques presented in this book have all been used to ship games, including some large AAA titles, so they are all practical and many will find their way into your audio engines. There are chapters about timed ADSRs, data-driven music systems, background sounds, and more. This chapter shows a system that plays ambiences, handling the looped and one-shot sounds differently. Looped sounds are played at randomized intervals, fading in and out and to new volumes. One-shot sounds are triggered individually with randomized panning, but can optionally be placed into groups of repeated sounds. Implementations are presented both using built-in tools from the audio middleware and using C++.