OP Amp amplifier circuit with output bias doesn't act as expected

ANY audio circuit that uses a dual supply can be biased at half the supply voltage and use a more simple single supply.
A precision rectifier circuit that uses a dual supply usually needs diodes to do the rectifying, but a precision rectifier circuit using an opamp that has inputs that go all the way down to its negative supply can use an inverting opamp circuit without any diodes and it rectifies perfectly.
A bandpass filter circuit can use a dual supply or a single supply, then its output can be rectified so that it is only positive levels.

@KlausST Thank you again for the advice. Especially the variable gain amplifier, that seems like a very good idea as I expect to have to do more tuning later on.

In regards to driving the LEDs I will probably post it here to verify my layout isn't terrible. Almost all the circuit boards I've layed out were completely digital.

@Audioguru You're right, creating bandpass filters with an output bias was super easy. I actually had all my bandpass filters simulated before this and I was worried that I would have to make major changes to them to remove the dual supply but it was very simple.

I'm considering if I should increase the supply voltage to maybe 9v. I saw that the preamplifer circuit you posted uses a 9v supply. I'm guessing the main reason for using 9v is so that the noise is relatively smaller than the signal.

My mic preamp uses a 9V battery because it is common. The cheap and readily available TL071 audio opamp I used has a minimum supply of 7V and works well with 9V.

Hi,

9V for yor system is not useful.

The increased supply voltage does not improve SNR (significantely), because the noise of an OPAMP is input referred, this means ...
If you want to increase the signal, then you need higher gain and this amplifies the input noise in the same way as the signal.
Additionally the increased voltage often is not useful, because the ADC has limited input voltage range.

Klaus