It's really interesting to see how EQ developed as a personal preference, rather than an engineering tool. Forgive me for doing the history thing, but how the electronics and the needs sort of had a race?
Engineers (as in electronics design engineers rather than music producer versions) saw equalisation as a must - from the early electronic music days, frequency management was a really big thing. Nobody had HF. They had the woofers, but no tweeters, bit it didn't matter because many microphones had no HF either. The turntable designs of the day had little up top either. With music radio, it too had no need for top end. Real engineers, though, were struggling to even keep the low stuff when they had to squirt it down miles of cable to remote radio transmitters or other studios. They started the design work on amplifiers that could have artificial boosting to allow for the losses in the cables. EQ was sort of born to fix this issue. Being a little flexible with time here, record technology progressed and the RIAA started the idea of EQ to cut the bass, then restore it later in homes. The upshot was that with the new small speaker tweeters - that came with the cyrstal technology for transducers of all kinds, HF content started to be captured and made it's way into homes. People still talk about baxandall as the inventor of the tone control circuit, but the real inventor was probably Michael Volkoff, just before the start of WW2. Engineers seem to be divided here because Volkoff's work was essentially on passive filters, as in cuts only, while Baxandall used amplifiers so he could boost. The early tweeters in home audio were passive - fed via a capacitor, which progressively blocked bass. Not really a crossover as it just stopped bass going into the dinky tweeter.
For a long time, EQ was just a tone control. Many PA systems of the 50's just had at best a bass and a treble on the output. The mic inputs were simply volume. Even a low cut switch to cut out stage floor noise was rare.
Then studio progress came quickly. Single treble cut, became bass and treble. Then a mid got added, then a sweepable mid, or maybe even a low and hi mid, both sweepable. By the second half of the 70s, we had graphic EQs, as soon as somebody invented the linear fader to do what rotary ones had done. 3, then 5, then 7 or more EQ faders on hifi systems and it's probably fair to say the smiley face and disco music were glued together from that point. Nobody set theirs flat, or reduced bass. Everyone was mixing knowing bass ruled and whatever bass decisions were made in the studio, home users would add a smiley face so bass and cymbals and high hats were everywhere - usually way too loud, but the genre stuck. Even orchestras upped the basses. They were almost pointless and nearly missing from early recordings. piles of violins and violas, a couple of cellos and a single bass were common. Now in a studio classical session we have upped the numbers and the balance!
As soon as we moved to digital, we started to do EQ things to the stage that analogue EQ couldn't do - they tried with cascaded analogue external units, but the notion of a full spectrum where huge boost or cut could be applied within an octave just was impossible. It's an effect, of course, not a real tone adjustment - but when I studied electronics in late 70s/early 80s, the thing I struggled with most was resonance theory. 1 over 2πfC still sticks in my head, and was tested in the exam where they gave you a filter circuit - with the resistance, inductance and capacitance values and asked you to calculate the frequency.
All this is simply history for us music folk - we really don't need to know how it works, because like picking a reverb or a certain Hammond organ tone, we just experiment till it's right!
I just cannot see any need to worry about how the EQ in our DAW does it. The one in Reaper is no doubt great. I cannot conceive how it couldn't be? It would be daft for me to suggest using my Cubase EQ in Reaper - what would be the point? If you are using it as an effect, with crazy curves to do something specific, maybe Reaper's one does it easier, or even more difficultly.
The OP is looking for an EQ method for tracking or even mixing. Personally I never use anything at all on the input - if I need to do something to make sense of it, I always do it on a channel - leaving the actual recording raw. I don't quite know what the rationale here is? Bouldersound mentioned one he uses - I wonder if this is simply because it's easier or nicer to control in a musical sense? I note that small movements in my Cubase EQ don't do much? Similar small movements in my live sound mixer seem to make things happen quicker? I doubt one is better from a measurement perspective, just from a user one. My Midas M32 seems to take more knob turning to add or cut things - that, I don't like compared to an old mixer that had knobs with a start and end.
Funny how an engineering requirement to compensate for physics in cables is now an artistic feature and not technical at all!
