With XLR signal connection/connectors, there are two possible "grounds". Signal ground and chassis ground.
Pin 1 is 'signal ground' and is the zero (0) signal reference point between pin 2(+) and pin 3(--). There is also a (fourth) connection point on the case, or barrel, of the XLR connector which is 'chassis' ground. It may or may not be the same as 'signal' ground, depending on the design of the circuit/component in question; often the 'balanced' connections in audio gear are really only pseudo-balanced; which is to say they are really two identical single ended signals, a 'hot' and a 'common' (or chassis ground) where one of the single ended signals has had its polarity inverted (the 'hot' is changed in polarity from + to --) and then it is re-combined with the non-inverted single ended signal to make a "kind of" balanced signal (which can then drive a balanced input on another component.) But it's not a true balanced output.
However, if you want to shield the signal conductors (in a balanced cable), it's best IMO to use 'chassis' ground, and connect the shield (at both ends) to the barrel of the XLR connectors. There is no need to 'float' the shield (connect it at only one end) with balanced interconnects, since there's no chance for any current that might develop in the shield to find its way into the signal path.
Just my two cents.
.
Pin 1 is 'signal ground' and is the zero (0) signal reference point between pin 2(+) and pin 3(--). There is also a (fourth) connection point on the case, or barrel, of the XLR connector which is 'chassis' ground. It may or may not be the same as 'signal' ground, depending on the design of the circuit/component in question; often the 'balanced' connections in audio gear are really only pseudo-balanced; which is to say they are really two identical single ended signals, a 'hot' and a 'common' (or chassis ground) where one of the single ended signals has had its polarity inverted (the 'hot' is changed in polarity from + to --) and then it is re-combined with the non-inverted single ended signal to make a "kind of" balanced signal (which can then drive a balanced input on another component.) But it's not a true balanced output.
However, if you want to shield the signal conductors (in a balanced cable), it's best IMO to use 'chassis' ground, and connect the shield (at both ends) to the barrel of the XLR connectors. There is no need to 'float' the shield (connect it at only one end) with balanced interconnects, since there's no chance for any current that might develop in the shield to find its way into the signal path.
Just my two cents.
.