my EQ plug-in has an input and an output and I'm wondering what to set these to, if say:
I boosted 2 decibels at 150Hz and 1.5 decibels at 6kHz; and then I cut 4 decibels at 500Hz and cut 4db at 4kHz
I'm assuming I set the output to -2dB, to even it with my highest boost.
how important are these EQ input and output?
They are gain staging points within your whole gain structure, which makes them important.
You have the right basic idea in that you want to try to use the output gain to compensate for what your EQ is doing. You can't go by the simple math you're attempting, though, because the amount of boost/cut shown on the dials does not necessarily directly translate into amount of overall signal boost/cut; i.e. Just because you boost such and such a band by 2dB does not necessarily mean the overall signal level will raise by 2dB. You need to watch your meters here instead.
With digital plugs, the input gain is not as important as it is with outboard analog gear, because you're not dealing with an analog preamp with it's own noise and distortion levels.
Really about the only time you need to worry bout the input gain very much is if the signal you're feeding it is much too high (clipping) or much too low (barely registering), and in all but special purpose cases that's usually best dealt with in the track itself. But for most cases (if you really want to cross your Ts and dot your Is) what you do is set the input gain so that when all your EQ controls are set to flat, the level of the signal coming out of the EQ is the same as the level going into it.
The output gain is much more important; there you generally want to set the output gain so that *after* you have set your EQ to how you want it to sound, the levels coming out of the EQ are more or less the same as they are going in, so that while there may be tone change, there's not much in the way of actual signal level change.
An important caveat in that last part, though, is that some tone changes will cause the track to *sound* louder of softer, even if the meters show little or no general change overall. This is where you HAVE TO use your ears to decide whether you want/need to push or pull the levels a bit different to compensate for that or not. (Come on, you didn't expect me to get through an entire post without having to refer to using your ears, now did you?
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G.
