Noise out iMac speakers

[iBram15]

Hello,

Every time I want to start a song, there is noise coming out of my speakers. When I plug in some headphones, the noise disappears, but there is no music coming out of them, and when I want to change the volume, this icon appears:

I've tried several things, like a reboot, or creating a new profile. But it's still there. Even when I boot in windows 7, I have noise (it's even continues).

Is it possible that it's software? Because it's only there when I turn on some music, even when I'm in mute. Or is it hardware, and should I call Apple?
(It's a 2011 iMac 27" bought in July, so I still have warranty)

Bram

 

[John T]

Or is it hardware, and should I call Apple?

Why not call Apple?

 

[iBram15]

Because I want to be sure if it is a hardware problem. I use it every day for work, and I can't loose it for repairing because I don't have anything else...

 

[John T]

Surely a simple 'phone query is worth a try? You may even get an answer to your query.