A lighter arrow is going to be loud because you dont have the resistance there. If your shooting straight, and there are no tuning issues and nothing is lose, I wouldnt worry to much about it. Add some limbsavers, string leaches, etc and see if that helps reduce some noise, You are not going to totally eliminate the noise. And by the time a deer would hear the shot the arrow is already in it so dont lose any sleep over it until you know for sure, if deer start ducking or jumping the string then you may want to check into a bit more but I dont think youll have to worry too much about it.