It sounds like, and the waveform confirms, that the mics weren't able to handle the pressure the bass put out. So while there's no clipping, there's plenty of distortion. There's no way to get rid of the distortion in post, you can only boost other frequencies to mask it. Running a steep roll off from 320Hz lessens the effect, but you can still hear it. If you have the 4.7k mod on the 853s, check your batteries. If you don't, get it.