Static-like sound from 27" iMac speakers

Question

I'm getting a loud intermittent static-like crackle from the left speaker on my 27" i7 iMac.
I originally thought it might just be hard drive noise, since it seems to correspond to heavy hard drive activity, but the sound goes away when I plug headphones into the headphone jack. The noise comes out of the speakers at the same volume regardless of the volume setting, even when the speakers are muted, but it goes away entirely as soon as headphones are plugged in (and there is no noise coming over the headphones).
Is there any possible software fix for this, or should I assume there's some loose connection in the hardware?

Answer 1

I've been having the same problem, it has been extremely frusturating. I just purchased a 21.5 a couple of weeks ago, and exchanged it a couple of days ago. The same problem existed (and continues to exist) with both computers. It seems the problem only occurs if I do the following:
Put computer to 'sleep' with headphones plugged in
Remove the headphones while the computer is 'sleeping'
Awake computer (with headphones unplugged)
I then get an extremely loud static noise from the left speaker. It is impossible to make out any sounds (other then the static), and the right speaker is muted. The static is only present if the computer is attempting to run audio (e.g. songs, garageband, alerts, volume controls, etc).
When I plug in the headphines, the sound is no longer present. I can then remove the headphones and everything seems fine.
I spoke to a 'senior support technician' via apple support on two occasions. The first time the told me to exchange the computer, the second time the tech asked me to run the computer I safe mode, go to the 'colonel-something', and I put my computer through several other tests.
The technician eventually requested I make an appointment with the 'Genius Bar' at a local apple store.
This is my first Mac (I've always been a PC user), and this has shed a dark-cloud over the company for me. Although the service has been good , its been a terrible waste of time, and I've never been so fruturated with a brand new computer.
If members of this forum are comfortable, I would request you put your computer through the steps listed above, and report your findings. I would like to know if this is a common issue, or if the store I got the computer from received a 'bad batch'.
If this is a common problem, and apple does not resolve this issue, I will switch back to PC. Although it may seem to be a minor issue, this is unacceptable for a $1200 computer.