If you have to hook up to the channel inserts on the mixer, just plug the 1/4 plugs to the first click not to interrupt the signal. Don't use TRS plugs in that case. And maybe put the recorder next to the mixer instead of 100 feet away??? You won't have balanced cables, so 100 feet away is not a good idea, anyway. Also, if they do use effects in the mixer inserts, you can make adapters to tap off the ring. If it's a real nice pro mixer, it may have 25 pin D-Sub connectors for balanced direct channel outs for recording. 8 balanced outs per connector. The recorder only uses 1/4 or 1/4 TRS for input. The D-Subs on the Roland are for SCSI drives or a digital R-Bus connections. Then you'll need 25 pin D-Subs at the mixer to 1/4 TRS at the recorder. With balanced lines you can go 100 feet then.