Hi, My name is ***** ***** certified computer professional with over 10 years experience. I will be glad to assist you with this. .I am sorry to hear that you are having this issue.
What is the model number of your Logitech THX speakers?
What is your windows operating system?
okay, thank you. Did you check the speaker cable from the system to the left speaker. It has a separate cable that connects at the bottom of your sub at the yellow connection. Make sure it is tightly fitted to each component.
Also check the audio balance settings on your windows 7.
Here is how you can check the audio balance in Windows 7
Go to Sound > Properties
Under “Levels” tab click “Balance”
Now you can adjust the volume for both left and right speaker, adjust them accordingly. Also Windows 7 is smart enough that which audio device this has been adjusted on. If you add a new audio output it will by default change to balanced each.
okay, thank you. This sounds like the jack on the pc may be bad. Try connecting another device(ipod, mp3 player, smart phone, etc...) to the Logitech and see if the right speaker will play. Let me know the results please.