I'm new to recording, having just done a couple outdoor concerts. I have a RH10 with small binaural SP mics. The recordings are OK, but I have noticable distortion from the bass and bass drums. I've read that a battery box will help with this. My question is, do I need to get the optional bass rolloff? And, if so, how do I know which of the 7 rolloff positions to use? I've tried to read past posts, but I'm just getting more and more confused. I've been recording with manual levels set to 9 or 10 for headroom, and with the sensitivity set to loud music. Thanks