You only use the AES terminator when you are using an AES source. The AES plug is placed at the end of the signal chain. Your first speaker gets a signal from the AES source, the next speaker is connected via the ‘thru’ port on the first speaker. Plug the AES terminator into the second speaker, in the ‘thru’ port. The AES protocol requires a terminator at the end of the line, without a terminator chances are that AES won’t work.