I've only really just started getting to grips with EQ and I've come to a stumbling block. I'm working with Apple Logic 8 and am using all of the preset synth and drum sounds, which sound fabulous on their own (no problem frequencies, in other words). However, there are obviously overlapping frequencies between instruments, because things are getting muddy. Given that I have to remove some frequencies from one already perfect–sounding sample to make room for the other, how do I decide which frequencies are expendable? How can I identify which frequencies are causing the problem? For example, if you have a guitar part, obviously you remove the low end, but what frequency bits should you take out in the rest of the waveform? A little bit of the 500Hz range and 1000Hz? How do you know which bits waste headroom? Also, is it best practice to reduce the overall level of an instrument and then raise certain frequencies containing the essential musical parts ('attack', 'body', and so on)? I'm not asking which parts of specific instruments should be removed, but am more wondering how I can identify which parts of a sound are useful or unnecessary. Is it common to have seven or eight steep (high-Q) 'notches' removing a number of frequencies in one instrument?