For years all I used was Real Track syncopated sugar because it has a great rock sound. So when I learned that there were many new distorted rock guitar Real Tracks available I ran to purchase the upgrade. Problem being that the new Real Track that I really like sound of is #631- PopAmericanDirty Ev 120 . However when using it with one of the most common rock progression I to IV in the 3 different keys I tried -the difference between the sound of the I chord and the IV is so different that it is unusable. Syncopated Sugar sounds real

Please advise.

WIndows XP SP3
Dell Latitidue D630
M-Audio Mobile Pre


Brand new HP Pav laptop Core i5 2.67 gHz 6 gb ram 500gb 7200rpm hd