Small Surround Sound Decoder Schematic
This circuit is not a requirement to replace the trade Surround decoders, because they have many more facilities and capabilities. But gives the opportunity for many to experiment with this type of decoding. The coding in Stereo Dolby Surround shows tend to be abandoned and replaced with purely digital DTS, Dolby 5.1 based purely on the level of digital processing and transmission of audio signal. As shown in fig.2 the stereo audio signal carrying the surround information is loaded on the Lch and Rch IC1A in IC1B, playing the role of the input buffer with the next steps. Then follow the steps an adder [IC2C], which aggregates the signals of the channel L + R and leads to the exit for the center speaker and a differential amplifier [IC2D], which shows the lag LR which is written in two channels, the information for the rear speakers. The output of IC2D leads one step adjustable delay sound to the rear speakers to create the feeling of space and adapt to the size of our site. It consists of IC5, which is a complete audio signal delay of 512 steps. The timing of IC5 is the IC4, which is an oscillator. The delay time is adjusted by changing capacitor C17. To cut noise produced by this process there are some filters in thereafter configured to cut the frequencies above 8KHZ and below 100 HZ or so, since they need higher frequency range for driving the rear speakers. The information is written back to 8KIZ to 100Hz range, which is why the rear speakers are small. These filters are around IC6A / B, which plays the role of the output buffer. All exits are potentiometer which help regulate the proper level of amplifier (megaphone) that follow. Clearly, each exit must lead an independent power amplifier The circuit is powered by a symmetrical voltage ± 15V.
