I have a question about ambisonic file use in FMOD, when I imported B format Ambisonic file from Reaper to FMOD, it’s always compress and having phasing problem, I would like to know is that possible to solve? Or if FMOD support ambisonic file?
FMOD Studio does not directly support Ambisonics. However, certain third-party plugins, such as the Resonance Audio Soundfield plugin that comes packaged with FMOD Studio, do support Ambisonics. As such, if you want to use ambisonics in FMOD Studio, you must use one of these plugins.
After I added resonance audio plug-in, there are only input but no output on my master track, do you know why and how to solve this problem? thanks a lot~
Resonance audio sends all its output to a resonance audio listener. You will want to add a resonance audio listener to a bus. You’ll need to open the mixer window and you can add it from there.
As tristanjl says, the Resonance soundfield and source plugins bypass our normal routing, as they process the signals from all such effects together, and output the resulting mixed signal to your project’s Resonance audio listener effect.
Thank you guys, it’s working! 
One more question, my ambisonic file is 4 channel, but the resonance listener only has 2 channel output, why is that?
Unlike the FMOD spatializer which can produce a multichannel output signal designed for surround speakers the goal of the Resonance spatializer is to produce a signal suitable for headphones. Advanced processing is performed to simulate how our ears perceive the real world (rendering sounds above, below and behind you more accurately) which naturally lends itself to producing a stereo signal. The output from Resonance isn’t designed for playing on speakers (stereo or otherwise).