I was getting popping in audio both in Smplayer & videos on other sites. I discovered the problem went away completely when I closed the X tab. When it was open, I noticed another glitch. I keep a small video windows to keep track of my sleep time. The elapsed time is displayed on them. Only when X was open it was throwing it off by about 3 seconds a minute. I closed it in Firefox & signed onto X on Chrome & all these problems went away. This is the only web site that has ever done anything like this. What is Firefox's problem with X?