So far no one's said why it's rubbish.
Aside from that, pin usage on the chip appear to be all wrong. Mic inputs to nand gate but output of gate is tied to some quasi funky common of all pins. Circuit is just, well not right.
I do not see how this thing could have worked at all.
so it doesn't work at all?
Perhaps you should build that futile circuit, just so you learn, not all web sites post decent material.