I have used TI filter tool design to make sallen key low pass filter, their are four op-amps stages. But filter tools has not calculated AC coupling capacitor that has to be included after every stage. We are amplifying audio signal hence both positive and negative cycle needs amplification. Otherwise the DC voltage that is being generated after every stage will make the amplification unsymmetrical. (Schematic is attached below)
Do we have to manually insert AC coupling capacitor or their is provision in the filter design software which I am unaware of.
Edit: After reading the comments, I have done changes in the circuit. Then I performed simulation in the Multisim. I am simulating only first stage of the circuit. And it is working according to the design. Can anyone please explain adding 100K ohm resistor between inverting and non inverting terminal is solving the problem. In my previous design I have made inverting amplifier using single supply, but V/2 (DC bias) was only given to non-inverting terminal of the op-amp. I was applying same logic for salley key configuration