I want to connect smartphone audio to this ic (M61530F).
When I connect smartphone audio,the audio is not clear and distorted audio. When I used the circuit shown in figure 2. Now the audio is not distorted but the volume is reduced by 90%.

Ihave no idea. suggest circuit.
Here is the ic audio input voltage and other factors

 

Why is the input ground connected to another input instead of the IC ground?

How are you generating the digital signals to control the volume?

What is the purpose of the Figure 2 circuit?

Do you understand how that IC works?

 

There is a gain control on FR input. Is it set to "0", or +5 or +10? Should be set to 0db.


I would add this circuit in between the phone and the 10uF capacitor. If there is still distortion reduce the value of the bottom 1k resistor. Maybe 470 or 220 or 100. On pin 2 and the gain set to 0db, the voltage should never get above 1.6 volts.