I can't see it on the black background, but I can see a faint grey inner circle on the white background. You must have eyes like a hawk.
In regards to the city, I don't know. It looks a little rushed for some reason, I know you've probably taken a while getting it right, but it feels little "after thought" like? Maybe the graphic equaliser look is the way to go?
Is the brand going to be city specific? If it is, you could incorporate certain skyline elements from the city?