Sound field effect processing circuit

Surround sound technology uses two speakers to produce a surround sound field with a three-dimensional sense of space (see the chapter on home theater sound systems). However, since this circuit is expensive, it is a cost-effective method
to only use oMS381 in a home theater sound system.
It is a cheap and effective sound field processing integrated circuit that can reproduce the orientation and spatial distribution of each sound source in the actual sound field
, creating a three-dimensional space surround sound field that is very natural and realistic, giving people a strong feeling of being there.
    MS381 has three functions: it can convert a mono signal into an analog stereo signal; it can work in a stereo pass-through
state; it can work in a space stereo state.
    The application circuit and working principle of MS381 are shown in Figure 5-38. This circuit only uses Among them, the two working states of 2 and 3 are: the
two-channel stereo signal is input to IC2 through the coupling capacitor q and C2. After being buffered and amplified by the internal circuit, the left and right channel signals
are divided into two channels, one of which has a gain of OdB and is directly connected to pin 3.16. The output is used as the main signal L and R output to the speaker;
the other signal is sent to the active phase shifter for phase shifting. At the same time, the active phase shifter realizes
anti-phase crosstalk between the two channels through the resistor and RP, resulting in The two mutual difference signals (L - R) and (R - L)o are output from pins 6 and 13 respectively through the electronic
selection The signal output by pin 6 is the same as the signal output by pin 3. The main signal is mixed to become the left
channel signal; the signal output from pin 13 is mixed with the main signal output from pin 16 to become the right channel signal. After the mixed
signals of the left and right channels are sent to the corresponding power amplifier circuits for amplification, the final signals emitted by the two speakers include L+R, L
-R, and RL signals. This is similar to the principle of SRS, so that two speakers can be used to produce
a surround sound field with a three-dimensional sense of space .