Sony STR-DE485 Audio/Video Receiver with Surround Sound (Discontinued by Manufacturer) Built-in Dolby Digital and DTS encoding for precise surround sound distribution to 5 channels Virtual Surround enables a simulated surround effect if you're using 2 speakers instead of 5 5.1 Channel input with surround control DSP (Digital Signal Processing) with 4 acoustic environments Sony Digital cinema Sound Cinema Studio DSP mode