I hope this is not the result of a bias, but I have to say, that looks VERY sexy. I always preferred this style for the spectrum visualizer than we have in other areas that appear as just vertical lines.. This is soo nice.
A suggestion could be to have some sort of blending/transition between the area the visualizer is in and the color just above it.
It also seems like you have it with some sort of transparency so that an color behind it won't matter.. it simply adjusts.. so maybe in that case, it does not warrant a different background area? If that is agreeable, then one issue may be when others may want to have the visualizer with a custom color later on.
This is really nice. Affects my mood anyway.. in a positive way.
After writing this I just realized that the spectrum visualizer is not very distinct for lighter colors.
They are not lazy... just more efficient.