For 5.1 content, copying to the sub wouldn’t overwrite original LFE content?
Also if I remember correctly after summing two channels one needs to reduce the gain by 10dB* (only the summed result, not the whole sub).
Well it is a cumbersome manual workaround with room for lots of manual mistakes. Realizing it is technically there only baffles me more regarding lack of proper UI for BM… I do believe it is one of the more popular DSP option in JRivar.
*From nanoAVR, as a reference:
