24 Chapter 1 An unbalanced 6-way interconnection uses 6 signal feeds and at least one ground wire, and so requires at least 7 pins in the connector used. Since an active crossover system is expected to reach high levels of quality, the use of balanced interconnections needs examination. The hot and cold signals from each channel can be wrapped by a single grounded screen, but ideally there would be separate assemblies of this sort for each channel, which makes for rather non-standard cable. Conventional balanced operation naturally increases the number of contacts on the connectors used to at least (6 × 2) + 1 = 13, though multiple ground connections would be good, not only to reduce voltage drops due to ground currents, but also to avoid alarming the superstitious end of the audio market. This assumes that the outputs are truly balanced, in that there are two outputs in anti-phase. While this gives a handy 6 dB increase in level over the link, the potential 6 dB improvement in signal-to-noise ratio is likely to be rendered irrelevant by the noise from the electronics. If we could drop the requirement for anti-phase outputs then we could have a quasi-balanced cable with 6 signal feeds, one cold line to sense the source-end ground, and one ground wire. The single cold line would be distributed to the cold inputs of six balanced input amplifiers at the receiving (power amplifier) end. The danger is, of course, that people would condemn it as " not a real balanced connection" though it would almost certainly give an equally good performance as regards common-mode rejection. This plan would require a minimum of 8 pins in the connector. 1.12 Multi-Way Connectors A multi-way cable requires multi-way connectors. It would be nice if active crossovers became so popular that a committee designed a special connector for us (like the HDMI connector, for example), but realistically that isn't likely to happen soon. It is therefore worth looking at what existing connectors are capable of meeting our needs. What we must strive to avoid is a connector configuration already in common use, because in the real world people are prone to plug stuff into any socket that will physically accept it. XLR connectors have the benefit of being fairly familiar, but they only go up to 7 pins. This is fine for 3-way balanced use, but only allows unbalanced 6-way operation (six audio feeds plus a common ground). Since we are dealing with higher-end systems, it seems inappropriate to rule out balanced operation. The familiar standard DIN connectors have a 13.2 mm diameter metal body and go up to 8 pins, so we can have fully balanced 3-way operation, or 6-way quasi-balanced operation, but not fully balanced 6-way usage. These connectors have some unfortunate associations with the low-quality DINs in the past, but today reliable high-quality versions are freely