sound problem

Hi

i have installed ubuntu 7 in my imac and when ever i plug in headphones in imac its speakers still sound + head phones as well.
why is it like this behaving.

everything works perfect i just can not able to shut off the voice from speakers when i plug in headphones.

I have never opened up the imac, but the switching *should* be hardware as far as I know. Do you have the same problem in osx? This could be software related, but I doubt it.

As I say, I dont have experience with the imac so I may be wrong.

Got the right Realtek drivers in Linux?

Why not go to System preferences, select sound, select speakers, and mute them.

I think this is a software problem. I run windows on my mac pro and the onboard speaker sounds all the time (despite the mini jack plugged into the socket on the back for the speakers). I have to have a mini jack plug cut off from an old set of headphones plugged into the front headphone socket all the time to shut it off.
I know this is a different problem, but it seems incurable to me.

Go into terminal and type in alsamixer. this will you give you control of certain functions and allow you to turn features on and off. (assuming you are using the Gnome Desktop)