I didn’t get scientific with it. It was just where it sounded good. Too close, and like Rob said, the side mic is pointed at the nut. Also, based on previous experiments, a fraction off center and you get a weird issue between the side mics. So placement in this case was done with the front and rear lobes of the side mic in mind as well as where I wanted the guitar to sit in the mix distance wise.Is the distsance for the room size? Or are you trying to use the distance to capture the full wave after it has completed propagation?
Whats the longest wave? A bass note low E..Like 27 Feet!