One of the bug bears with using an active crossover is the issue of ground loops that can intrude as a hum or buzz. In most but not all cases this is mitigated with balanced equipment inputs and outputs.

However, the balanced system relies on the absolute cancellation of the common mode noise signal on the differential signal. This is very much determined by the absolute impedance balancing of your balanced output of your equipment and balanced inputs. A mismatch of 1% can have serious detrimental effects on the effectiveness of balanced connections.

Secondly, balanced equipment inputs are in face much noisier than unbalanced inputs. A balanced input typically has a signal to noise ratio of -104 db. An unbalanced input is typically -117 db. This has to do with a trade off between common mode noise rejection which requires high impedances to work and the inherent noise of a high impedance circuits. The noise performance can be significantly improved but it’s more expensive to design and manufacture so most equipment manufacturers not bother to tell you this.