No Audio

I was messing with the usb audio controller with one of the sliders on the sides I don't remember which one. I was messing with one now and I can't get the audio to come back. I tried playing with the sliders for a few minutes trying to get it back on, but I just cant get the audio to come back. I have music playing in the back on my computer trying to listen to see if the audio will come back on, it won't come back.