Different woods have different tonal qualities... therefore making the guitar have different tones under different circumstances. Your SG is most definitely made of Mohogany which is a pretty dense wood. This allows it to transfer large wave frequencies better than most light woods... Where as the tighter frequencies tend to get mellowed out due to the density and weight of the wood. The Ernie Ball is probably a more "Strat type wood" (alder, poplar, basswood, ash... etc.). These woods are lighter thus making them brighter... You don't see a lot of people playing tuned down guitars that are made of any of these woods... because they don't get the deep growl that Mohogany does... You are probably comparing the Mohogany tone to that of the Ernie Ball.. and they're not going to be the same. Mohogany is it's best when used for deeper tones...