Most bows do tend to be a little louder with three-under. Maybe it's the change in tiller, but I don't know for sure. Generally, the nock set needs to be higher. If using a recurve, put a strip of moleskin between the string/limb contact area. Don't be afraid to use enough string silencers, either. And using a heavy enough arrow always helps. I've been shooting three-under for decades, and have always been able to get my bows silenced. In theory, a longbow should be quieter than a recurve. Don't give up on the three-under, 'cause it can really help your accuracy. I recommend it to anyone having a problem with accuracy...it usually helps them very quickly. Good luck!