Missing Mouse Click audio

I see (hear) many videos where typical mouse clicks produce a nice sound from the iMac (sort of like a stylus taping on LCD screen).

My iMac is silent. I've gone into Preferences > Sound but can only select sound through the headphones. Plus the selection is limited.

Help?

Thanks

Tom

I figured one of my problems, if you plug in external speakers the setting in the sound settings window will read HEADPHONES, if you unplug the external speakers it reverts back to INTERNAL SPEAKERS.

Now all I need to do is find the audio effects sounds I'm looking for as the selections afforded in the sound window are limited and not what I want.

Tom