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Quick Tip : Subtractive vs additive equalization
Mo Volans on Fri, January 14th 1 comments
When enhancing your sounds with EQ there is a fine line between a light sweetening and an over-colored, or over-hyped end result. Most of the time any negative results are due to too much additive equ

When enhancing your sounds with EQ there is a fine line between a light sweetening and an over-colored, or over-hyped end result. Most of the time any negative results are due to too much additive equalization, in other words too much gain in any one particular frequency band.

Relative beginners may think that using additive EQ is the only way to enhance their sounds but there is another way. Let's take a quick look...

01 - Using Additive EQ

So if you are new to the idea of subtractive EQ techniques, when you want to enhance a sound you will most likely reach for your favorite EQ plug-in and dial in a healthy amount of  gain into the required band.

This will usually work pretty well and as you can hear here this drum loop is nicely brightened using the high frequency bands in Logic's Channel EQ. You may notice it's already sounding a little 'hyped' though, this means the added frequencies are a little colored and over processed.

Imagine this effect on ten sounds across a mix. You could end up listening to your EQ plug-ins, rather than the original audio files you loaded. So let's check out the alternative...

(Original untreated loop)

(Loop with hyped high end)

02 - The Subtractive Alternative

Here we have the same sound but instead of adding high end I have used a shelving filter to remove some of the sounds lower frequencies. This may seem counter productive but combine this with a significant raise in level and the final outcome is a boost in our higher frequencies.

The real difference here is that we have not actually 'added' any processing, instead we have boosted the sound's high end qualities by subduing it's other prominent features and bringing the level of the overall sound up.

So in the end ... we are hearing more of our sound and less EQ and that is never a bad thing!

(Loop with more natural subtractive treatment)

Want to learn how to improve your mixing technique? Check out Sonic Dimension in Mixing, Logic 403 - Mixing R&B, Logic 404 - Mixing Electronica, Pro Tools 402 - Mixing Pop in Pro Tools amongst many other tutorials here.

Comments (1)

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  • KS2 Problema
    An important topic that tyro recordists should give some attention to. Of course you *do* have added processing when using *any* EQ. Even if one uses a strictly passive EQ (filter, no gain) you are still processing the signal, regardless of whether you are working in the analog or digital domain. Not only that, an active filter is simply a passive filter with gain elements added into the circuit. Going a bit farther, with the shelving filter examples given, IF the shelf curves were set up as true equivalencies (overlapping corner frequencies) -- they're not in the example, of course, the low shelf and the high shelf would leave the 'middle' frequencies unaffected as per the graphic representation -- but if they were, and equivalent makeup gain was used after the subtractive pass, the results would be the same, assuming neutral gain processing in the EQ circuitry [gain without saturation or other signal distortions]. The POINT of subtractive EQ vs additive is probably more pertinent when considering the example of a somewhat narrow band that the recordist feels needs more 'definition.' If he exclusively boosts that narrow band (or conversely lowers *everything* else and raises makeup gain) he may get the effect he thinks he wants when considering the track in solo -- but chances are, when he gets it in the mix, there will still be a lot of sonic information in the other frequency bands that is not necessary to the mix and adds distracting detail in bands that may not be carrying the *musical* information. Sometimes, often, even, it's better to remove sonic information outside the desired bands than to boost the desired band. It's not really a *technical* exploit -- but rather a change in thinking and philosophy -- that, used as a gentle and general guide, gets the recordist into thinking about reducing the influence/impact of 'unnecessary' sonic detail -- which will tend to lead the recordist to cleaner, tighter mixes, as a general rule.
    • 5 years ago
    • By: KS2 Problema
    Reply
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