I have a Diamond Hornet 70lbs @29" and two Bow Techs (50 Defender and 07 Allegiance both set at 70lbs). I can shoot either vanes or feathers from the Hornet with no noise. Feathers through either of the BowTechs cause noticable noise (I have tried two different shafts with the same results). I haven't figured out why...I just stopped shooting feathers. I personally like the feathers better but don't like the noise.