Speaker BJT Amplifier - very low gain
The gain of the last stage is approximately equal to:
$$Gain_3 = {{R8}\over{R4}} = {{4}\over{2200}}=0.001818$$
You must use a push-pull emitter follower. Transistors desirable to take a large gain. With such a supply voltage using two stage voltage gain enough (\$Gain=1000 \div 5000\$) output and push-pull emitter follower (gain approximately equal 1). The last stage can be done on a single-ended power transistor with the radiator cooling. But modal current in this case is very high.