@kota1 thanks for the info! I saw the 30 day home trial, but assumed I'd be on the hook for return shipping if I didn't keep them. Shipping those heavy beasts would likely be expensive.
Do you know how close I can run the 580's to the wall (unfortunately the port is on the back and not the front)? We are planning a dedicated theater room in our renovation, and I'd like to keep the speakers flat against the wall, so I can run an acoustically transparent screen in front of them without using a bunch of room depth. The JBL's might be perfect for this application.