Get rid of white line under site logo

[speakeasy media]

I want to eliminate the white line under my logo. I get that it's the background image, but I need plain English vB for Dummies instructions for how to cover it up. See red arrow pointing to the line in question.

The logo is a rectangle with the blue color (matched by eyeball to the default vB blue color) all the way to the edge of the image, so I don't see why there's a gap for the background to be visible through.