In some cases, you may not be able to monitor mono or dual mono audio from Final Cut Pro X 10.2 in OS X 10.10.3 with third-party audio devices like these:
- Universal Audio Apollo Twin (Firewire)
- Native Instruments Komplete Audio 6 (USB)
- Blackmagic Design Multibridge Pro 2 (PCI)
- AJA Kona LHi (PCI)
- MOTU Ultralite (USB)
You can resolve the issue by following these steps:
- Open Audio MIDI Setup.
- Select your audio output device in the audio device list.
- Click Configure Speakers in the bottom right of the window.
- Click Multichannel.
- Choose Stereo from the pop-up menu and click Done.
Learn more about Audio MIDI setup:
For more information on audio channels in Final Cut Pro X 10.2, read these topics in Final Cut Pro X Help: