ahh yes! makes sense! 

Just FYI - the VST 3 version of SPAN only accepts one stereo pair in, but the VST 2 version accepts 4. If you want to look at multiple tracks at once, it is easier with the VST2 version. You can create sends from your audio tracks to a new buss, and the second send will have a SPAN-Input 2/3/4-Buss X option. The VST3 version can be used on 2 mono tracks by panning the sends L/R and routing in SPAN, but SPAN only allows 4 groups, so the VST2 version still "maxes" out at 4.
 
Here is a nice webpage to get started with it (SPAN can do a lot more than you initially "see"). http://music.tutsplus.com/tutorials/how-to-use-voxengos-span-part-1--cms-20778

mettelus
Just FYI - the VST 3 version of SPAN only accepts one stereo pair in, but the VST 2 version accepts 4. If you want to look at multiple tracks at once, it is easier with the VST2 version. You can create sends from your audio tracks to a new buss, and the second send will have a SPAN-Input 2/3/4-Buss X option. The VST3 version can be used on 2 mono tracks by panning the sends L/R and routing in SPAN, but SPAN only allows 4 groups, so the VST2 version still "maxes" out at 4.
 
Here is a nice webpage to get started with it (SPAN can do a lot more than you initially "see"). http://music.tutsplus.com/tutorials/how-to-use-voxengos-span-part-1--cms-20778

Or i can throw it on my master bus and just solo the tracks I want to monitor through SPAN, right?  
 
 

alewgro
 
Or i can throw it on my master bus and just solo the tracks I want to monitor through SPAN, right?  

Yes, you can do that. However, it's not very helpful because usually you're interested in seeing how one track fits with another.
 
The next step up in sophistication would be a multi-track analyzer that can superimpose more than one track in a single display for easy comparison.
 
SPAN Plus ($40), for example, is the multi-track version of SPAN. Best of the bunch is MMultiAnalyzer ($64, frequently on sale for half price) from Meldaproduction. 
 
 

Bit has a good point. The free version of SPAN (VST2) will superimpose up to 4 "scenes" but will only allow you to see two inputs at a time (can color code each group (input set via routing assignments), and show one other group as an "underlay").
 
Sorry if I confused you with that earlier post.

I use the analyzer from NugenAudio
http://www.nugenaudio.com