Noisy BTL Audio Amplifier Circuit
The first thing that struck me, starting looking from the left, that made no sense to me is your \$2.5\:\textrm{V}\$ reference. Why only \$10\:\textrm{pF}\$? Why \$1\:\textrm{M}\Omega\$ resistors?? It just doesn't make sense on its face.

Then I started looking at what the inputs of the opamps "see," looking backwards. And it's not even close to balanced, for either of them.

Then I saw the resistors and diodes as your "current source" for driving the output BJTs and knew that would be a problem. Then I wondered if the NE5532 could even hope to drive that thing, bad as it already was....

And then I saw the output diodes and nothing else mattered anymore.

Take a look at the polarity of the diodes tied across the resistor+emitter to collector of both \$Q_2\$ and \$Q_4\$.

Do you see any problem there?



EDIT: Okay. So that problem is really just a "typo" in your schematic.

Let's start at the beginning. You are going to all this trouble with a BTL topology and for all your trouble you intend on running this with only a \$5\:\textrm{V}\$ supply rail? Is that true? Or are you flexible there? What kind of output wattage do you expect to deliver into the \$4\:\Omega\$, \$3\:\textrm{W}\$ speaker? Explain your thoughts about your half-rail reference voltage design? (And yes, you will probably need feedback.)