Hello everyone I too was having the same issue with static on all audio on video/youtube/streaming movies I fixed mine and no longer have the issue DELL Tech support is USLESS! and its sad the people that are designed to know the pc in and out couldn't be further from the truth! So take the steps below and it should correct the issue!
1. Right click on your speaker icon on on the lower right handside of your tool bar at the bottom, select SOUND.
2. You should now be in the 1st tab called PLAYBACK, which will list your all your audio sources. Locate the one that says SPEAKERS/HEADPHONES right click on that one and look for PROPORTIES.
3. Click the ADVANCE TAB and select RESET TO DEFAULT, the click on the ENHANCMENTS tab make sure the SETTINGS is selected to NONE and make sure all the boxes are UNCHECKED you may need to select apply you may need to restart your computer and BOOM no more static! hope this helps guys