Small surround sound decoder circuit

The picture below is a small surround sound decoder circuit. You can use this decoder surround sound system with your home audio system to make the audio system sound more "live".

Parts List:

How the circuit works:

Operation of the circuit begins when a stereo signal carries surround information in the master volume section of the circuit. This drives the left channel Lch connected to models TL072 IC1A and IC1b, where the right channel Rch is connected. The outputs of these op amps will be used as input buffers for subsequent stages of the circuit. IC2C is responsible for adding the signals from the left and right channels to power the center speaker output, while IC2D is responsible for adding the phase difference between the left and right channels, which is encoded in both channels and fed to the rear speakers. It is necessary to ensure that the negative terminal between the rear speakers is not connected to ground, as they will only operate in parallel with the main speakers.

The output of the IC2D will power the audio conditioning delay units for the rear speakers. This will result in creating an appropriate sense of spacing based on the size of the room. This will contain the operational amplifier sound delay signal IC5 MN3004 with 512 stages. Since IC4 MN3101 is a clock signal, it provides timing to IC5 as it is used as an oscillator in the circuit. Variable capacitor C17 regulates the delay time in the circuit. The presence of filters in the circuit is to prevent noise generated during this process. These filters can be adjusted to cut frequencies above 8 KHz and below 100 Hz so that they can drive the rear speakers. The rear speaker is small because its input is encoded with a bandwidth of 100 Hz to 8 KHz. The filter is built around IC6A/B, which is also an output buffer. A potentiometer is placed in each output to help adjust and modulate the speakers and amplifiers. The power supply in the circuit is 15 V, and each output can drive a single power amplifier.