Semiparametric EQ is a simplified version of an EQ I cover much more often in my EQ tutorials as well as my free EQ cheat sheet, parametric EQ. There’s value in a semiparametric EQ’s simplicity, however, so let’s talk about how it compares to parametric and more importantly how to use a semiparametric EQ.
What is Semiparametric EQ
As I covered in my overview on the types of EQ, whether we’re talking parametric EQ or semiparametric EQ, the “parametric” refers to the breadth and depth of the parameters or settingsassociated with that EQ.
As the name suggests, semiparametric EQ features far less… features than its parametric peer like my favorite overall plugin, FabFilter’s Pro-Q 3.
Many of the EQ settings you are familiar with from a traditional (as we think of it) EQ are missing. While some semiparametric EQs are exceptions, they typically don’t feature a spectrum analyzer, the slope setting, the Q setting, the ability to create different EQ filter types, or feature dynamic EQ functionality.
So what are we left with?
Most semiparametric EQs feature three bands, a controller to specify where each begins and ends relative to the others, and gain knobs to boost or attenuate each. Ableton Live’s stock “EQ Three” is a prime example of a semiparametric EQ:
Some semiparametric EQs also feature an occasional high or low pass filter, as well.
How to Use Semiparametric EQ
Without all the bells and whistles we normally associate with (parametric) EQ, you may wonder what’s the point of semiparametric EQ?
As you might have guessed, semiparametric EQ is not for surgical adjustments to the frequencies of your audio.
Instead, semiparametric EQ is for broad strokes for overall tonal adjustment.
Trying not to sound too much like a Dos Equis commercial, I don’t always use semiparametric EQ, but when I do, I’ll drop it at the front or end of my signal chain for the track I’m applying it to.
I like to use Ableton’s channel EQ specifically for that purpose:
Its “Low” and “High” dials work as a low shelf and a high shelf, respectively, by default (there’s an option to change it to more of a pass filter, as well).
When a track is feeling a little flat, clogged, muddy, etc. I’ll boost a little top end to achieve a better balance.
Conversely when a track is feeling thin, a little low end boost via a low shelf adds some body.
Alternatively, we can also take away a little of the top end when a track is feeling thin to better prop up that low end via subtractive EQ to achieve that better tonal balance.
These are subtle changes, mind you; while I referred to semiparametric EQ as being for broad strokes, I’m generally not adjusting anything more than 2-3dB in either direction.
The idea with semiparametric EQ isn’t to fix the entire track with one plugin. I’ll almost certainly follow that initial three band EQ with Pro-Q 3 (or the best FREE EQ plugin) which allows me to roll up my sleeves and make the kinds of specific EQ adjustments which I recommend for each instrument in my EQ cheat sheet.
At the end of my signal chain if the track still feels like it could benefit from more low or top end, I can do that with one final instance of a semiparametric EQ. Again, these are subtle changes, even more so than the intro instance of the plugin as I really shouldn’t need TOO much adjusting at this point.
In this case, like match EQ on the master bus, we’re simply giving the track’s frequencies one last finishing touch to get it where we want, and while it’s not always necessary or something I always use, semiparametric EQ is great on a track level for achieving just that.