This is a simple Surround Processor with the degital delay method. This audio processor is not using any special function ICs that difficult to get parsonaly, and desined in only general purpose ICs. Of course the Digital Delay Block of A-D, D-A and delay logic is also using only general purpose ICs. This is the key feature that easy to build it. The type of this Surround Processor is generating the surround effect with processing two channels of stereo source. Most of those are generates the surround effect with separates reverberations from source signal and applies any processes, and then mix it to front channels or output as rear channel. Separated reverberations are applied to delay as sounds refrected in the hall. This is important process on the every surround processors. Delay time is tipicaly several ten miliseconds, and this time affects the tendency of the surround effect.