Ayman

It's not enough just to check the wiring. Use a scope, check signals, learn something about fault finding. You need to know this if you are going to be a decent engineer, and the only way is to stick at it until you get somewhere. And don't be too proud to get help from your prof, if it costs you points, so what, but LEARN. Alwyas make sure you LEARN from your mistakes ("what did he do that I didn't do that made him succeed where I failed?")

The fact that you are fixated on a 16 ohm speaker shows you don't understand enough basics too. Almost certainly, what the chip says it can handle is a speaker of MINIMUM 16 ohms. 22 ohms would not cause the problem.

But you should check that you are getting a decent signal with a scope BEFORE you connect the speaker, anyhow.

Learn to solve problems in small stages, instead of floundering around seeking help from people who cannot possibly help you ... who then get irritated ...