If the AIRA Compact E-4 is connected to a Mac via USB but is not recognized as a USB MIDI device, check the following points.
- USB cable and port
Use a USB cable that supports data transfer. A charging-only cable cannot transmit data. If the Mac has more than one USB port, try a different port. - macOS version
Depending on the macOS version, the E-4 may not be recognized as a MIDI device right after connecting. Try connecting the USB cable while the DAW is already open, then check again whether the unit is recognized. - AIRA LINK mode
Set AIRA LINK mode to "Off" when connecting the E-4 to a computer. To turn it off: hold [AUTO PITCH], [HARMONY], and [VOCODER] together to enter menu mode, press [▶/●] (play/record) until "OFF" is shown, hold the three buttons again to exit menu mode, then turn the unit off and on again.