Send to Compressor sound problem

Hi,

I need to test properly to confirm it happens every time:

It seems that when I send a project to compressor that has background noise removal on the audio the file (H264 mp4), it comes out with the sound horribly warped and 'underwater' as if the removal's been too strongly applied (and not how it sounds in playback). This is with multicam clips with a separate audio track (Zoom H5 wav), cut on a project timeline.

Where I need to test is that I sometimes convert everything in a project timeline into a compound clip to raise the overall volume - and I'm wondering if this is causing an issue.

When I export as a master - or direct to Vimeo, I don't get the same problem.

Anyone experienced this or anything similar?

I've found that the built in background noise removal in FCPX is inconstant and buggy.
I always use the Logic Denoiser filter in the specialized category of audio effects.

Thanks Mark, that's a really helpful tip