There's really no hard and fast rules to follow when it comes to which specific frequencies to boost or cut. It always comes down to what kind of signal your performance of your bass on your system produces. But there is a process for figuring it out each time.
To begin with you have to have ready access to the studio monitors you're going to be mixing the music on. Without this there's nothing you can do to figure it out.
So you set up your bass and your preamp into the interface and record the performance into your DAW. Then you apply a parametric EQ to the track. You grab one of the middle bands and turn it up until you start to hear it making a very noticeable difference to the sound. Then you slowly sweep the band up and down the spectrum until you find a spot where it makes the track sound better. Keep sweeping it up and down in smaller and smaller increments until you find the best spot for it, where it sounds the best. Then you play with the gain and width of that band until it sounds as good as you can make it sound.
That's the basic process for EQing.
Sometimes you need to make a cut instead of a boost, but only if you hear a specific problem with the signal that you want to get rid of. It sounds like you will probably need to make a cut to get rid of the flub and to bring the attack of the pick down to a better level.
The flub you're hearing is always caused by too much energy in the low frequencies. It's a little easier to get rid of this. You're going to use the high pass filter in your parametric EQ. This is the part of the parametric eq that is all the way to the left at the low end. It looks a little different from a typical band.
What you want to do is grab the high pass and turn it on. It will immediately start cutting out the lowest frequencies in the signal. Then you slowly sweep it up from the bottom of spectrum while listening very carefully to the track. When you hear that the flub is gone stop sweeping it to the right and instead slowly sweep it to the left to bring back some of the lower frequencies. Keep going until you hear the flub come back. Then sweep up again, then down again, over and over in smaller increments until you find the spot where the high pass gets rid of the flub without cutting out any of the rest of the sound of your bass. That's one problem down.
You're going to do basically the same thing for the attack of the pick, but with a low pass filter instead.
Turn on the low pass filter, the one at the far right of the spectrum, and go through the same process. Sweep it down and back up the signal until the pick attacks go away, but the rest of the bass sound is intact.
If you find that with either the high pass, or the low pass that you're losing too much of the bass sound you want in order to get rid of the problems, then all you have to do is make the slope of the pass that's cutting too much of the sound you want steeper. A steeper sloped cut will have less of an effect on the rest of the signal.
So you're going to record your bass through you system, and then while listening to it on the monitors, in this order:
1. High and low pass the signal (I can't tell you which of the two to do first because I can't hear it. sometimes the flub is so loud you can't hear what's going on with the attack of the pick properly, sometimes the attack of the pick is so loud you can't hear the flub properly. Start with whichever one sounds loudest.)
2. pull up a band in the middle somewhere (probably in the lower middle portion, but it's all up to your ears)
You do it in this order because you always want to get rid of the problems first before you start making boosts to your signal, or else the problems will mask the changes you're making and you'll have to redo it anyway.
That's how it's done in the DAW.
On your darkglass it's a little different.
Make sure you can hear your bass through the darkglass, through the DAW, through the monitors. Turn all of your EQ knobs to the 12 o'clock position.
If the flub is louder, start with the flub. It's always in the low end somewhere. So play a bit, listen to it carefully, then turn down the low knob a bit and play again and listen again. If the flub's not gone do it again, turn it down a bit, play listen. Do this until the flub is gone, then play with it up and down until you find the best spot for it, where it cuts only the flub and leaves the rest of your bass signal.
Then the attacks you don't like. Those are always in the higher frequencies, so grab the treble knob and do the same thing you did with the flub. Turn it down slowly and listen to it until you find the perfect spot for getting rid of the attacks. I don't know what your signal looks like, so this knob may not be enough to fix it completely, but it will probably make a big difference.
If instead the attacks are louder, do the same thing but start with the attacks.
Now that your problems are as solved as possible, time to get it sounding how you like.
Start with the Low Mids. Play your bass a bit, listen to it carefully and then play with the knob. Turn it up and down while listening until you find the sweet spot.
Then the Hi Mids. Same thing, play with the knob while listening to the bass until you've got it sounding just like you like it.
And you're done.
