So how do I...

[iMacJunkie]

On my new iMac, what settings do I need to change in system preferences to:

1. Turn off the speakers?
2. Keep headphones on and playing?

 

[J&JPolangin]

On my new iMac, what settings do I need to change in system preferences to:

1. Turn off the speakers?
2. Keep headphones on and playing?

On my late 2009 iMac I just plugged in the 3.5" jack and it took care of itself... my mid 2011 is in process of a clean install so I naturally figured it would be the same but I'll let you know if I have problems when I'm finished...

 

[neonblue2]

You don't need to change anything. If you plug in headphones the speakers stop playing audio.