Here's the setup in AMS: PCR800 keyboard/controller connected via usb to mac mini. Set to use internal MIDI interface in the keyboard. ( I've tried both settings) DSI Tetr4 connected to Mac Mini via USB. (Logic can send Midi from keyboard to this) Eridol UM880 connected to Mac Mini via usb. Appears in AMS and can have devices connected. Appears to work, but... Yamaha FS1R connected to midi port 4 I/O of UM880. DSI Evolver connected to midi port 3 I/O of UM880. I am able to create midi instruments for all of the connected midi devices. I have double checked the midi channels to insure they are correct. All devices have their audio outs going through an external mixer to speakers and I can hear them when triggered by on device buttons. The Tetr4 can receive midi and it does sound through speakers. Neither of the other units respond to midi generated from the keyboard, but the midi indicator in logic shows they are receiving midi input, They just don't sound. In summary, devices connected through USB (class compliant) seem to work. Regular midi devices connected through the UM880 do not respond. The FS1R will respond to midi input throughout the um880 when I put the keyboard midi I/O directly through the UM880 and manually select the FS1R. Mac mini 2.66Ghz 750 GB HD 8GB Ram is running Snow Leopard 6.8. Logic version 9.1.4. I am at wit's end about what to do to make the MIDI devices work in logic. Any help is greatly appreciated.