The ACS RC limbs are recurve limbs and the ACS are longbow limbs.I have a set a ACS RC limbs,very fast but are a touch noiser then the longbow ACS limbs,I'm comparing to my A&H ACS longbow.I haven't shot the Dryad ACS longbow limbs,but plan to get some in the future to go with my ACS RC limbs.Like said mine were alittle bit noiser then my other bows.What I did on mine set the brace right at 8" or slightly above,used bow hush and placed the silencers at the 1/4 mark for the upper and the 1/3 mark for the lower silencer and was shooting arrows 10 GPP.It shoots alot quieter where I have it set up now,but I like to play around with different things.I plan on playing with some different string materials,I have a 6 strand 450+ on it right now but have D97,8125 and 8190 to try.Most of the low stretch strings seem to have different tones on different bows.Some are quieter with one more then another one.I'll play more when my new Dryad Orion riser comes in,right now I have my limbs but no riser.