A Simple Rule for When to Use a Dynamic vs a Static EQ.

So you’re working on a song and you’ve found a frequency which you want to adjust. Let’s say you want to nudge down 4.4k a little bit to reduce a bit of harshness. Now you ask yourself: what type of EQ should be used?

As time passes by, there becomes more and more dynamic EQ plugins available. Besides, in Ableton, Bitwig, and other DAWs, it’s easy to make any automatable EQ plugin act as dynamic by the use of envelope followers. On the other hand, when using a dynamic EQ plugin, there may be times when you want to use the bands as typical, with no reactivity.
So, we have a pretty much open choice of whether to use a static or dynamic EQ on a track we’re working on. So what to do?

Static for constant changes, dynamic for momentary changes.

Static EQ: Overall Energy

Use static when you want the EQ change to continue unabated over the entire course of the time range you’re working with.

For example, an electrical noise which hums throughout a track and is being notched out might stay active the entire time.
Having access to an analyzer which tracks the average energy (be it rms-based, ebu, or otherwise, not just the maximum peak attained) can be valuable for gaining an insight into which frequencies are building up the most over an entire song. A frequency that only momentarily peaks might be just fine to keep in a song, helping to retain its original vibe.

Dynamic EQ: Peak-to-Energy Ratio

Use dynamic when you want the EQ change to only occur at certain select moments.

For example, during mastering, there might be a particular instrument which is too bright, but lowering that frequency over the entire mix would darken other elements containing that range when not needed. By setting the EQ band to only trigger when the too-loud instrument strikes, the rest of the mix remains untouched the rest of the time.
For this method, comparing the average to the peak energy of a spectrum can be useful. Places where the peak energy is too high, but the average is good, might be good spots for dynamic EQ bands to focus.
To use this method, you’ll want to carefully set (and sometimes automate) the threshold to only trigger exactly when you want it to, acting a bit like a frequency-selective limiter.
By pushing the threshold so that it is triggered most or all of the time, the audio will be “swimming” in the dynamic reactivity, making a dynamic EQ mimic the way multiband compression is more generally used. When trying this, slower response time can help smooth out any encountered over-jitteriness.
WARNING: it might be tempting, and is more than possible, to smooth out every single untoward frequency variation that occurs, but overdoing this can kill the original vibe of a piece of music, making it sound bland and formulaic. Try to maintain at least some of the original tonal dynamics, and only carve out what really needs to be.

Drawbacks to Either

Possible drawbacks to using a static EQ: it ruthlessly carves away at a signal, reducing it continually. This can sometimes be a bit oppressive and unnatural-sounding at more than subtle amounts of boost or cut, particularly with high Q values. It also alters the phase, or adds pre-ringing in the case of linear phase EQ, either of which may or may not be a problem depending on context.

Possible drawbacks to using a dynamic EQ: basically, the same problems that compression can incur. Due to physics, an audio waveform with dynamics applied to its level cannot avoid being distorted, and this problem becomes more obvious the faster the response times are.

Both dynamic and static EQ plugins incur phase offsets as well, though for dynamic EQ the phase offsets will be dynamic as well… which can make them better, or worse—depending on how it’s been applied. Dynamic linear phase EQ plugins will have dynamic amounts of pre-ringing. Interesting.

Refined Control: Automation

For a happy medium between static and dynamic, or to give yourself more refined control of the exact results,  don’t be shy about using automation to alter parameters. For example, a static EQ band could be automated to reduce in intensity during a particular moment, or a dynamic EQ’s frequency position could be changed gradually over time. Using automation literally adds a new dimension to the capabilities provided by equalization tools. Simply because you can nowadays so easily use automatic dynamics tools doesn’t mean you should shy away from still using automation for next-level, personalized professionalism in your work.

Try “riding the fader”: map a hardware controller slider or knob to an EQ band’s gain parameter, make sure the automation arm button is on, and play through your song, recording the automation moves you make as you ride the fader. This will give a “human dynamic” EQ, which will not slope and curve and react exactly the same as the automation of anyone else, nor any plugin, will. Just like playing beats on a pad controller rather than programming them will result in a more personal sound, riding the fader of various parameters throughout arrangement and mixing will literally imprint a bit of your soul onto the results, helping your music to avoid an overly robotic, inorganic feel, providing a feel of “your personal touch”. Which, to me at least, is far more valuable to artistry that transcends time than any technical perfection in one’s craft based on existing standards one might acquire is.

Automation can be useful as a fix for overdoing something, rather than completely removing an EQ that was placed. For example, if you notice that a static EQ works for most of a track, but during one section it alters a particular instrument too much, instead of just rage-deleting the EQ, you could automate the bands during that specific section to morph it into a different curve altogether, by punching in fader rides and then manually cleaning up the resulting automation for smooth transitions. Likewise, EQ automation can be done to further enhance what is already there—for example, boosting in intensity and shifting upward in frequency during the chorus section of a song to help it pop.

Of course, if you like robots you can also set up complex envelope followers and ai-reactive plugin chains to respond in nifty, musical manners as well. Perhaps combine both; automating a macro by hand which scales the overall intensity of the auto-reactive dynamics. Human and robot, working together. How nice.

It’s shameless promotion time! For the performodule ableton pack that includes my most deeply-tested and innovative dynamically-reactive ai-style effects, please check out DynaMixing Ultimate at Isotonik Studios, an epic bundle featuring multiple full packs of effect racks centered at providing specific results for various tasks during mixing, condensed into one mega-pack. To install, you just have to drag the pack into live, click the confirmation message, sip your tea, and have access to all the good stuff directly from your browser.

School’s out… for… summer.
Keep your mind dynamic!

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