No increase and decrease sound - just alerts

[sparkie7]

I have upgraded to El Capitan on Mac Pro 2008 3,1. When I press the sound increase and decrease buttons in the top function row - there is no beeps or sounds like in 10.6.8 that I was running prior.

When I go to System Preferences > Sound > Sound Effects - the Select an alert sounds all work, but when I slide the Output volume left and right on the slider - there is no sounds/feedback whatsoever.

I have selected Line In and Line Out for Input & Output respectively.

Any ideas why there is no volume up and down sounds?

PS. Also noticed that the Optical Audio out port at the back of the Mac Pro is lit up red - is this normal? and has something to do with the Sound issue?

Any help appreciated

 

[Ritsuka]

There is a checkbox below the in the same preferences panel.

 

[sparkie7]

Thanks. Found this...

Go to System Preferences>Sound>Sound Effects, and check mark Play feedback when volume is changed