Just want to share my experience with you guys about this setup.

I been playing around with the 30-60° dual kinect setup for a while and got pretty nice results, but still saw some glitches specially when turning around, wanted to try the 180° setup, problem was that didn't have enough cable for that so I ordered 2 24ft USB extentions from amazon (the ones sugested on the wiki).

Till now the kinects worked ok pretty much on any USB 2.0 port I connected them (except the 3.0 ones no idea why), making sure there where on different controler of course, have 6 USB 2.0 and 2 USB 3.0.

One week waiting for the amazon package and I got the cables, all cool and stuff but for starts, they didn't work pretty well, iPi Recorder just crashed after a couple of minutes of running, the error was that the device just stopped working, this never happen when connecting the kinects directly.....

Ok first thing I though was that my cables where defective but I did some tests and they worked fine, so why were my kinects crashing? after investigating further, and using only one of the cables I notice that only the kinect with the extention cable crashed and not the one connected directly.

I did some reading on this, a few hints came up on the forum about USB not having enough bandwith or power to hold up the devices, so I remember having a similar issue with my old computer and USB portable harddrive, the device just stopped working and to solve this I had to disconect other devices to make it work.

Later I found out that was my wacom tablet the one hogging all the power from USB, and also the extention cables consume more power from the USB than connecting kinects directly to pc , so to solve the issue I had to change my tablet to one of the free USB 3.0 slots, and also rearranged the other devices to balance the load, after that I haven't had a crash again.

So in short its mostly a power thing and can be solved by balancing your load on the USB or maybe disconnecting other stuff when you user the recorder. It took me a whole day to figure this out on my own, hope it helps.

Almost forgot to mention, Im only using one extention cable at the moment because I set up one of the kinects close to the pc.