When it comes to choosing an EQ, I find that there are two different outcomes I'm looking for, and that will steer me towards one of two genres of EQ. For instance, there are occasionally problems with a track where EQ is the best way to deal with things, whether the problems be ringing, boominess, or a general buildup of frequencies that I want to eliminate. In those instances I gravitate towards very clean-sounding surgical EQs. The Maag EQ4, by Plugin Alliance, is nowhere near being in that camp! This EQ is colorful (obviously, look at those knobs), and is drop dead simple to use, but the simplistic controls mask a very deep plugin.
As you can see, the controls are very sparse, mostly consisting of a fixed frequency controlled by a gain knob. That may seem very limiting, but it's an extremely well thought out design. The gain is stepped in .5db clicks, and I never thought I'd say this but I can totally hear a half decibel change in many of the bands. Adding .5db at 2.5kHz and 40Hz makes kicks and snares more powerful. Adding .5db at 650Hz and cutting .5db at 2.5kHz makes electric guitars less buzzy and sit better in some songs. I sometimes find myself adding a decibel or less of just one frequency band, and moving on to the next track.
The main reason I bought this plugin is because of the peculiar Air Band, which you can see goes all the way up to 40kHz, way past what humans can hear. I don't know what kind of voodoo is in this thing, but I can add 4-5db of stuff only dogs and bats hear, and it sounds amazing. I may be adding gain to a shelf that high, but it's affects reach into the high end of human hearing, and it's pretty obvious to hear what you're doing. I tend to pop this plugin on vocals, acoustic guitars or horns, set the Air Band to 40kHz and raise the gain til it sounds angelic, then back the gain off a bit. We can't have things sounding too angelic, can we?
It wasn't until after I'd demoed the EQ4 and bought it did I spend much time messing with the other bands (the Air Band is that good!), since I thought the choice of fixed frequencies was too limiting. While the EQ4 doesn't always work out, it's a beautiful sounding bit of gear when it does. The amazing/hidden genius of this plugin lies at the extreme low end, not just the extreme high end. The Sub knob isn't labeled with a frequency, but I've heard that it operates at 10Hz. That's right, there's another range you can control that is outside of human hearing, this time it's subsonic rumble.
All in all, this is a great sounding and very easy to use EQ, and I find myself using it a lot on vocals, pianos, acoustic guitars, and even on my mix bus.