Hello there Harris Miller,
It sounds like you are not getting any sound out of the external speakers that you have connected to your iMac. I would take a look at this info from the article named:
OS X Lion: If you can’t hear sound from your speakers
http://support.apple.com/kb/PH3837
If you’re trying to listen through external speakers
- Make sure the speakers are plugged into the audio out port (or, if your computer has only one audio port, the audio port) on your computer or computer’s display, and if necessary, into a power supply. Check for a power switch and volume adjustment on your external speakers. If necessary, turn the speakers on and try adjusting the speaker volume.
- Choose Apple menu > System Preferences, click Sound, and then click Output. If your computer has only one audio port, choose Sound Output from the “Use audio port for” menu, and then make sure your external speakers are selected.
- If you’re trying to listen through speakers or headphones connected only to the USB port on your computer or computer’s display, choose Apple menu > System Preferences, click Sound, and then click Output. Make sure the external USB speakers are selected. Then, open System Information (in the Utilities folder in Launchpad), and make sure you see your speakers listed.
If your external speakers still aren’t working, check the information that came with your speakers.
Thank you for using Apple Support Communities.
Take care,
Sterling
