I'll disagree with those blaming body design. Body design can certainly shape midrange and below, but most sparkle is directly radiated off the strings. I've got a baritone jumbo, which by some of the advice here you'd think would be lifeless as a wet dishrag. With new strings, it's plenty sparkly, and if I'm doing any of the other things talked about, the top end neeeds to be controlled. The quarter pick on brand new strings actually sounds like a very aggressive exciter setting. I've done both, and in an otherwise fine take that just needs more shimmer, the exciter works well.