Hey,
I stumbled across the master spectrum, and to be honest, I am not very familiar with mixdown or mastering… (yet, I really want to know more about it, it is very interesting 
) And I was wondering if there were certain things about the master spectrum I have to know…
Does this for example look okay? If you have anything else to say about the master spectrum, please do it 
Well the highs and especially the hi-mids seem to be bit lacking, but hard to say because I don’t know what type of music it exactly is. Also, always mix and master by ears, not by values and graphs 
One helpful thing you can do with the scopes is to cut out a section of a song that you like the production on for whatever genre you are dealing with and play it back in renoise. Study the scopes as that song plays and you can get a general idea of where to go when trying to get your own frequencies sorted out. Granted, this only provides an insight and will not hand you all the hit making secret powers. I have gotten some mileage out of doing this, anyway.
The scopes also reveal frequencies that the ear tends to miss or that some equipment fails to reproduce well. Sub-bass and sometimea transients in the higher frequencies are things i don’t always hear well during mixing and can cause major problems when played back at good volume on a p.a., nice car stereo, etc.
Use the the tools as reference material but let your ears be the final judge (to more or less re-spin what noby said). And also, don’t pump the sub-bass on your mix too much; let the amp and eq used to play back your groovin’ tune handle that part. Leave the end user some control, ya know? Otherwise your cut might get chucked. I know this from sad and somewhat embarrassing personal experience.