Hi rockman9974
You probably already know that the main advantage of using a GPS clock source is that it allows systems to record the same timestamps into recorded media such as video, without having to actually connect the systems together. However, it takes a very sophisticated system to allow audio sync to be maintained by GPS alone without using large (high latency) audio buffers in each device. For this reason, it is a lot cheaper and less complicated to rely on connections between the audio devices for sync. It is then a case of picking your ‘best’ device to act as the clock master, and setting all other devices to sync to that. Some people like to use dedicated word clock generators, but in my opinion, the most reliable clock to use is the iLive internal clock. As the iLive is (presumably) handling most of the system IO, it makes sense not to use some external source, which could fail during a show, causing some kind of glitch or interruption in the audio.
External sync is mainly for situations where the iLive is not the most ‘important’ device; perhaps it forms part of a larger broadcast system, or is running the monitors only. Another reason to use an external sync is to interface with a device that does not have the option to sync from the iLive: in this case the only option is to sync the iLive from that device via DARS, word clock, etc. If you are trying to choose between word clock and DARS, my suggestion would be to use word clock, as it is more widely supported, and can be more easily distributed using a dedicated word clock distribution box. In terms of performance, there is no real difference with iLive between any of the supported sync inputs.
Hope this help.
– Jeff, A&H