# 3D stereo sound circuit & Split stereo signal & Balance Indicator

This is a create a special 3D stereo sound circuit. Which sound is a dimension to the listening. Using the same low frequency to appear out the left and right continuously. Interspersed with master frequency. By signal frequency is mono system passed through this circuit. The low signal frequency and Frequency prototype will take turns, out of the left-right output. Alternating signal because it has been triggered from the oscillator circuit.

The working principle

The working principle of IC1 is an astable oscillator circuit, that can produce pulse frequencies out of about 14 Hertz, to trig an IC2 work, by separated out to “Select C”.

Figure 1 is complete circuit of Create stereo sound 3D.

Where have the mono signal come to through both input A and B at pin 4 and 5 of IC2 in sequence. Which signal from input A will go to output 1. Next, the signal from input B out to the output 2. And in short time or around 1 mS or 0.001 Secoud.

The output will come back from input 4 to output 2 and from input B to output 1 switched continually all times. To connected capacitors, C2 is low pass filter some section from input A. Next, signal send to input B. And then, the C3 prevents the humming signal that may happen of frequencies 50 Hz from AC main. This output can connect to the stereo amplifiers or the stereo headphone is even better.

The input may be a radio signal to the TV or other mono signals. How to build this projects This project we make on base to experiment with the 3D stereo sound system so can put all components on a universal PCB board in Figure 2

Figure 2 how to put all components on the universal PCB board.

Components lists

Resistors 0.25 W +5%

R1: 100K
R2: 1M

Capacitors

C1: 0.1μF 50V Polyester
C2: 0.68μF 50V Polyester
C3: 10μF 16V Electrolytic

Semiconductor

IC1: NE555 timer
IC2: CD4053 ANALOG MULTIPLEXERS/ DEMULTIPLEXERS

Others One Universal PCB
9V power supply circuit using 7809

## Split stereo signal circuit

This Split stereo signal circuit model to are simple at use in fining wideness of a signal stereo. Which be valuable very for an earphone stereo. or the system that the opening between a loudspeaker too much.

The working of Circuit That generally stereo signal will have mix do not separate the left-right clearly. It already really appears that way channel on the left has will a signal on the left total up with stereo signal on the right work character of the circuit, begin at, input A, and B that have IC1 and IC2 build with buffer circuit.

A signal from IC1 and IC2 will change come instill the circuit of IC1 and IC2 which build be Inverting Amp circuit at having the expansion ratio equals to 1 a signal that has changed this circuit already will opposite with Input A and B.

This circuit must use, a power supply regulator model positive and negative 15V will make this stability circuit improves.

## Stereo Balance Indicator Circuit

This is Stereo Balance Indicator Circuit.

You have a stereo system. But the level of both channels right and left are not the same. Yes, you can adjust with the Balance button.
But it’s quite difficult to adjust fine and accurate.

Like Water level gauge in construction. We need to find a balanced level of 2 points in order to install the shelf on the wall.

So in this, we use Stereo Balance Indicator to check it.

### How to use

Connect both input right and left to a power amplifier.

Adjust a sound signal until both LEDs go out. Shows that both audio signals are well balanced.

In contrast, if the sound signals are not equal level. One of the LEDs will light up.

## How it works

Sure, I try to keep a simple circuit. This circuit too.

Look:

Include 4 transistors, two LEDs, 4 resistor and 2 capacitors only.

Shall I explain its process?
Here is:
Apply 9V power supply(battery) to the circuit.

Enter the audio stereo signal into both the input left and right channel.

C1 and C2 pass audio signal and block DC to the base of Q4 and Q2.

If the stereo signal is equal. Make Q1 and Q3 conduct the current is the same too.

So not the difference of voltage. They cause both LED1 and LED2 goes out.

But if the stereo signals are not the same.

Suppose that

The Left channel is louder than right. It causes Q4, Q3 works. R2 passes the current to LED2. It glows up. But LED 1 goes out. Because Q1 and Q2 do not work.

On others hand, the right channel is higher than the left. Make Q1 and Q2 work well. LED1 so glow up instead.

#### Parts you will need

Q1-Q4: BC147 NPN transistor
C1, C2: 0.01uF 50V Ceramic

0.25W Resistors, 5% Tolerance
R1, R2: 2K
R3, R4: 470 ohms

LED1: 5mm RED LED
LED2, 5mm Blue LED

9V Battery

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