I think no matter what, 3 under is noisier than split.
I shot 3 under for years and made bows with negative, even, and positive tiller. They were all noisier when shot 3 under.
About a year ago I switched to split and noticed several things:
– Less wear to the nock set on the string
– Less wear to my shooting glove
– Less noise / vibration in the bow
I can’t say it improved my shooting though 😳
Here’s an interesting article about tiller: