JSter said:
My very first suggestion is to stop comparing frequency curves. You might as well compare automobile quality by the shape of the silhouettes of their respective bodies.
Regardless of what you see on the screen as a correlation between smoothness and professional quality, bumps in a frequency curve are not necessarily a bad thing. Nor is smoothness necessaily a good thing (you want to listen to pink noise all day? That's about as smooth of a curve you can get.)
While a great car may have a sleek silhouette, putting a sleek silhouette on a Yugo will not make it any better. It's confusing cause and effect, form and function. The fact that commercial CDs have smoother curves on them is the end result of a lot of factors in play. Hammering a curve into a similar shape will not magically make your mix sound as good, because that's re-creating the effect without paying attention to the causes.
So what's causing your bumps? It could be gear coloration like surfmaster says. It could be acoustic coloration in two ways: it could be the acoustics of the room in which your recording or it cound be the response of your monitoring chain and the acoustics of your control room (if they are the same room, then there could be a double whammy.) It could be your ears.
Or it could just be that those bumps represent the actual proper response and relative levels of instruments and vocals that you're mixing; i.e. that those bumps are *supposed* to be there.
The fact is that the vast majority of the time there's no way to tell from looking at an RTA display alone whether those are good or bad bumps, whether the curve should be smooth or chunky. You gotta fall back on your ears to do that.
If the mix sounds good to you and most others, then screw what the RTA is telling you. If the mix sounds bad, then fix it according to what your ears are telling you, not by what the RTA has to say. If you can't yet trust your ears, then that's what you have to work on more than anything else, because an RTA is not going to tell you what you need to know the way you think it will.
G.