DE9 is a digital audio format developed by DTS, primarily used for high-quality sound in home theater systems and music streaming. It supports multi-channel audio, allowing for an immersive listening experience by delivering sound from multiple directions. The format is designed to be compatible with various devices, including Blu-ray players and streaming services. DE9 enhances audio clarity and detail, making it popular among audiophiles and movie enthusiasts who seek superior sound quality in their entertainment systems.