One of the three speakers has noticeable hiss. That one's going back.
With a long AES run (like 25' per cable) I get no sound from the FIRST speaker in the chain. The second still plays. A shorter cable between the speakers solves the issue. Never had this problem with the 708p. Obviously the first speaker gets the signal, so I'm not sure why it fails that way.
I suspect this is a termination issue when chaining multiple (greater than two) speakers.
The JBL 70XP speakers don't properly configure a termination scheme where the last speaker (and only that speaker) has the proper 110 ohm AES terminator.
Each speaker has its own 110 ohm terminator and if you continue adding speakers via the feed-through jacks, the parallel combination continues to further load the source. This seems to work okay for two speakers, but when you start adding third/fourth/etc, you will run into a problem.
I fail to understand how they messed this one up.
The proper way to do it would be as the Dutch & Dutch folks have. You have a portable 110 ohm XLR connector that plugs to the feed-through jack on the final speaker. Since the speakers themselves do not have a termination internal this scheme works correctly.
This is not unlike an old 10-base-2 ethernet system or the CAN Bus in your car. Chaining multiple devices works well as long as you terminate at the last device and don't have any "stubs" along the way that can cause reflections.
Dave.