Thanks for that explanation (I hadn't thought of it that way) - if all that was done with the sub-frequencies is what you described, that would be different than actually covering up the tuba sounds. These days, it is probably more of an issue on the streams than in-person problem, although I have heard a few shows live this year that had overpowering "goo" happening. Are you saying that none of the corps are doubling the tuba octave? It sure seems like I am hearing some synth patches that are "boosting" the tuba - or is it just overtones? I agree that it could be a topic unto itself.