The Truth About Additive and Subtractive EQ
A battle that’s raged on for decades: additive vs. subtractive EQ. Many online forums have seen this topic, from the earliest days of audio production blogs to a few discussions that have gone off the rails in our own forum! People develop opinions, and whether the opinions are their own or ones that have been accepted from a colleague or mentor, they spread them.
Unfortunately, when opinions get spread as fact, the truth gets pretty hard to find. Consider this your proverbial needle in a haystack of biased judgments passed from engineer to engineer. The holy grail of EQ knowledge the can finally answer the question:
“When and why should I use additive (or subtractive) EQ?”
Dispelling The Myths
Do you know why people get so entwined in the battle between subtractive and additive EQ? It’s because EQ is such an integral part of our tools as engineers that we close our minds to anything that isn’t part of our normal process. Most engineers don’t intentionally become narrow-minded; we’re conditioned that way through practice and repetition.
We hear phrases all the time that reinforce our biases…
- “Additive EQ adds color.”
- “Additive EQ just tries to add what isn’t there.”
- “Subtractive EQ makes things sound better.”
- “<Insert GRAMMY-nominated engineer’s name> only uses subtractive EQ.”
By playing devil’s advocate, a lot of these everyday “facts” that support one side of the argument can be disproven pretty quickly…
- “Doesn’t subtractive EQ also color the sound?”
- “Can’t you use additive EQ on what IS there?”
- “Isn’t ‘better’ a subjective term?”
- “Good for them, but what about the hundreds of others who use both?”
I’m not saying anyone should go out and pick fights with everyone they hear defending one side or the other. Just keep your mind open, your ears sharp, and ask yourself these questions the next time someone tries to give you their biased opinion as if it were fact.
When To Boost (Additive EQ)
Let’s start with the one that seems to get the worst rap – additive EQ. For some reason, people have had a vendetta against additive EQ, claiming it does more harm than good, that it tries to add something that’s not there, and that it’s an amateur’s easy way out that professionals would never take.
Wait – seriously!?!
Guess what guys and gals? I use additive EQ. I’m pretty sure most professional engineers I’ve worked with over the years uses additive EQ, and if they don’t, they certainly haven’t said I’m wrong for mixing my way. I’ve learned some great tricks over the years that hinged on – you guessed it – additive EQ.
You see… boosting is as much a tool for your mixes as subtractive EQ. The difference is, you want to boost when your audio needs more of a particular frequency band. For example, a vocal without enough air can benefit from boosting higher frequencies with a high shelf filter. A snare without enough crack will benefit from a mid-boost at its fundamental frequency.
Engineers that try to accomplish these things using their “subtractive EQ only” approach usually end up taking the long way around and doing more harm than a few dB of boost ever could. They’re draining a pond to catch a fish, killing a lot of other fish in the process.
When To Cut (Subtractive EQ)
That’s not to say subtractive EQ is worse, it’s just used in a different scenario. Subtractive EQ is best utilized when you’ve got too much of a frequency band in your mix. It’s the yin to your additive EQ’s yang. Everything you’d want to use additive EQ on to get more of, subtractive EQ can be applied to hear less of.
Let’s use our same two instruments again, but this time with inverse problems: a vocal where the singer is too breathy and a snare that’s ringing too much.
The singer’s problem can be fixed with the same exact shelving filter we used to boost some air into the vocal, but this time it’ll cut instead of add. The starting frequency and amount of reduction needed will change with each voice, but the tools do exactly what you want them to.
Your snare is the same way – too much ring can be a nightmare, but if you can get it dialed out with EQ without throwing the rest of the frequency spectrum out of whack, subtractive EQ is your friend. Some engineers choose to focus on their overheads and room mics first with subtractive EQ – remember, sometimes bleed can be the root of the issue too.
Perhaps the most common use of all subtractive EQ comes in the form of hi-pass filters. Many engineers use these simple yet effective filters to roll off low-end rumble and unwanted bass build-up. It’s a great technique when used correctly, and really makes room for your kick and bass to round out the bottom of a mix.
Just remember: too much subtractive EQ and you’ll find yourself boosting frequencies back in later on in the mix.
EQ Power Tips
There are a few things I recommend doing to get the most out of your EQ, especially when both additive and subtractive EQ are being used on a single track. Take these tips worth a grain of salt – everyone has their own workflow, these are just the methods that help me move quickly and efficiently through a mix.
Subtractive EQ Before Additive EQ
Most of the time, I will cut out the bands that have too much frequency content before I boost anything I need more of. While there are exceptions to this approach even within my own workflow, I’ve found that creating a (generally) flat, baseline sound to build on is generally easier to work with than adding frequency content and then trying to subtract some of it later.
I like to think of subtractive EQ in a way that’s similar to compression early on in the mix – it’s a way to tame my sound so that I can mold it into what I want to hear once it’s under control.
Leave The Solo Button Alone
Another huge piece of deciding whether something needs additive EQ or subtractive EQ comes from listening in context. To fully appreciate a sound and its needs, you should be hearing it as the tracking engineer did – in the mix.
Ideally, using the solo button sparingly during the EQ process should give you full context around each instrument and how it’s interacting with the mix. You won’t need to worry about your kick drum disappearing behind your bass when rolling-off some deep lows – by mixing in context you can hear exactly how the two are interacting on-the-fly.
Want More?
If you’re interested in debunking other common myths and learning my personal techniques for a killer mix, be sure to subscribe to our newsletter below. We put out blogs twice a week addressing some of the biggest concerns we’re faced with as engineers and producers.
Once you’re ready, come on over and join the discussion on the Joey Sturgis Tones Forum on Facebook – just leave any biased-opinions at the door; we don’t need any more debates on which is the superior EQ approach.
See you there!
