Can anyone tell me whet the best way to set a nock. Is it best just to use a D-Loop and no brass nock or a combination of both?

I am using both at the moment. The bow is quite loud at the shot and the string leaches want to come out of the string I have tried serving them in. I am thinking that the nock (GT nock) is being held too tight.

What do you think?

Regards

Dan