About a month or 2 ago, I ran into a problem when viewing videos with Firefox. I normally run Firefox on a Linux Mint computer system. Software is the current updated software available thought the Linux Mint Repository. However, I confirmed this same problem on a computer of mine which runs on Windows 7-64. Same problems with same solutions. The problem is that I get a sound echo when viewing some videos. This started out as only happening when watching movies on the CWTV.com. But more recently it has progressed to when watching some videos on YouTube.com. I normally watch TV movies from their source, CWTV in this case. I get the echo sound right away with CWTV movies. The only way that I can hear the sound properly on CWTV is to hit the "Pause". The video imagery will continue with a single sound track. But I am unable to pause the movie at any point during the movie. This is 100% repeatable every time. YouTube is different. I get the sound echo again. But when I hit the "Pause" on these videos, a single sound track stops and I can hear the echo sound continuing. But the video imagery also stops. In short, the video stops, but the echo sound continues. This only happens on some YouTube videos. My solution has been to download those videos and play them with my system player. At no time do I have extra tabs or windows open. Note: I can watch movies on HULU and Amazon without this sound echo occurring.