I just purchased the ProMedia 2.1 speakers through Amazon. Here is what I am experiencing.
1. When speakers are connected, there is a constant buzz, all the time. I can decrease the volume on the speaker an it will go away, but then the volume is too low to hear anything.
2. When I unplug the speakers from the iMac headphone port, and I plug in a headset, there is no buzzing in the headset, and it sounds amazing.
3. When I shut down the computer, the buzzing does stop, when I reboot and the system powers up, the buzzing will start, will have 5 "pops" and then just the constant buzz. This would seem to point to the soundcard, but again, headphones sound great in the same port.
4. I checked the sound preferences, but there isn't much that can be changed.
5. I did an SMC and a PRAM reset on the iMac, no help
6. I have the iMac plugged into a UPS (CyberPower 1500 full Sinewave system). I initially had the speakers plugged into the UPS (not UPS outlet). I moved the plug to a different outlet, but it didn't help the issue.
Any ideas out there? I can't think of anything else to try. Are these speakers just too powerful for an iMac? I could reach out to Apple, but my guess that being headphones sound great in this same port, they will say that there system is running fine.
Thanks in advance for any help you can provide.