I have a set of stereo speakers for my computer from the "Creative"
My problem is rather recent in that when I turn on my speakers and play a video on the net..I still hear sound from them even when the sound is all the way down to zero. If it is a YouTube video for example, I have to use the YouTube volume control to turn it down so I can moderate the volume on my own speakers.
This does not seem to happen when I play a CD or a MP3 on my computer, it appears to happen only when I play something from the internet.
Ok..here is an update..I was listening to music samples from Amazon and the volume control was normal but for YouTube vids or videos from places like "Albino Blacksheep" have that issue.
If you're using Windows 7 or Vista there might be a "component" for your sound. For example, I have different levels of sound from I am listen to Youtube and say Newgrounds. I found out that when a flash video is playing that there was a "plugin" on my sound mixer I turned it up and down and it still seems independent of the stuff that plays on Youtube.