My experience with most drum heads is that over time they go dead and lose their resonance and good tone. I've used many different heads from all of the major manufacturers. About nine months ago I put Aquarian Response 2 heads on my Gretsch Renown kit. I have Classic clears as resos. Not only have these heads not lost tone but they are actually better sounding than when new. I really can't explain it but it's true. Anyone else experience this?