Posted on 19. Mar, 2016 by Daniel Duskin (Record Producer, Mixing & Mastering Engineer) in EQ, Mastering, Mixing
There’s has been a lot of discussion, debate, and educational material on servicing subtractive versus additive EQ in professional mixing and mastering.
Generally, the trend in suggesting a “proper” technique has leaned toward subtractive EQ in recent years. Is this advice correct? I would like to offer my professional perspective on this topic.
Subtractive EQ simply means that you are reducing the gain of one or more of the filters on an EQ. Additive EQ simply means that you are boosting the gain of one or more of the filters on an EQ.
Subtractive EQ is a bit more difficult to understand and apply, which I believe has contributed to the popularity of teaching subtractive EQ as a technique of authoritative modern educational wisdom.
Let’s face it, mixing is very misunderstood, and all beginners struggle to obtain the sonics they are striving to achieve.
Because of the mysterious nature of mixing, and the continuous need for a “quick fix,” we often assume the solution must exist in an area that is less understood and more difficult to apply.
Sometimes this is the case, but often it isn’t. Just because you’re struggling to get a good mix doesn’t mean the solution must be one of those techniques you don’t have a good grasp on.
It’s important to note that when applying additive EQ, you will be thinking about problem solving differently than while you are applying subtractive EQ. I’ll touch on this more later.
While the technique you choose matters, the ultimate path to a good mix is enough experience to understand what you are hearing, an honest—critical—ear, and trusting your instincts.
With that said, I’ll dive into the benefits of both subtractive and additive EQ—where each has it’s strengths, where each has it’s weaknesses, and developing the right technique for you.
Let’s start with additive EQ—or “frequency boosting.” Additive EQ has many benefits that are more immediate than subtractive EQ. First of all, frequency boosting has immediate and noticeable benefits on the contents of a mix. For example, if you need a guitar track to cut through the mix more, simply boosting the high mid’s, or even boosting a high-shelf will immediately reveal this technique as a useful solution to a problem, because it works! Anything that gets quick results has substantial value as a technique, so it’s very important not to write it off as an “improper technique” if it’s working. If it works, it’s right!
Let’s face it, when the mix is done, nobody is going to look at your EQ settings and judge your mix based on those settings. They are going to make a judgement on that mix based on how it sounds, and nothing else. They can’t see your EQ technique, so what sounds good is what’s right—period.
Now that we’ve looked at the benefits of additive EQ, let’s look at two of the downsides. First of all, if you aren’t continuously gain-staging after boosting a frequency, you could be fooling yourself into thinking that the frequency boost is the best move, when simply pushing up the fader on that channel ‘might’ possibly give you a better result.
This is a psychoacoustic phenomenon I like to call “louder, brighter, wider, better” in which we tend to prefer anything that is louder, brighter, or wider, in any given A/B test—even if it sounds worse in context of the song itself.
The other downside I’d like to mention is that the boosting benefits you are gaining sonically don’t always sound better than a subtractive technique used to fix the same problem—sometimes it sounds better, and sometimes it doesn’t.
For subtractive EQ, I’ll tackle the pros and cons in reverse order. Starting with the cons. The immediate downside to subtractive EQ is that it’s not very fun. That might sound silly, but let’s face it, when you are turning things down, it’s generally not as exciting as turning things up—and one important factor in getting a good mix is enjoying the mixing process. Your mixes tend to sound better when you like mixing.
Your mix is a performance, just like playing any other instrument, and if your performance lacks passion, that lack of passion will be heard.
The benefits of subtractive EQ are usually slow to grasp, but can be substantial—especially when you finally grasp the concept. Subtractive EQ forces you to find the problem and remove it, instead of faking yourself out into believing things sound better simply because some frequencies got louder.
Because any sonic improvements of subtractive EQ are more honest, and less likely to fool you into thinking it sounds better when it doesn’t, you will feel better knowing that when you find the solution in subtractive EQ, you have made the right decision.
If you just want to know which technique I prefer so you can skip all of these details and use some hard and fast wisdom, I’m sorry that I’m about to disappoint you.
I use both techniques often, and rather equally.
While there are no hard rules on what is the best technique, I’ll give you an example where subtractive and additive EQ can work together to get good results.
I usually start with subtractive EQ. High pass—and sometimes low pass—filtering is often the first EQ move I apply, followed by notching out any problem frequencies I might find.
This is a good way to clean up your tracks as a pre-mix.
When reducing frequencies ranges, it’s usually best to start with a narrow bandwidth.
Filtering and notching should usually come before any compression (but not always). Boosting frequencies usually comes later.
For example, if you want to make a kick drum cut through the mix and sound big and powerful, you could boost the high-end and boost the low-end, but some of the problem could be a boxy sound in the low-mid’s (or high-bass).
While boosting the highs and lows will lessen the perception of the boxy sound (it’s all relative—remember that), directly notching out some of that boxy low-mid frequency will make it easier to get the right amount of high and low shelf boosting, and that combo will usually (though not always) give a better result.
It’s important to understand that subtractive EQ and additive EQ require a different type of thinking when it comes to problem solving. When filtering or notching out frequency ranges, you need to think about sonics that are bothering you that you want to remove (or at least reduce). When boosting frequency ranges, you should probably be thinking about what you want to cut through (or stand out in) the mix.
Now, here comes a perspective that might take all of this technical mumbo-jumbo out of the costs and benefits of subtractive and additive EQ, and give you a reason to relax and stop worrying about it so damn much.
All of this is relative, literally! Most instruments have a limited frequency range, have resonant frequencies, and frequencies that do close to nothing. When you boost one area and then reduce the output level of the EQ to properly gain-stage, it turns out that reducing the opposing range and boosting the output gain of the EQ often gives a strikingly similar result in the mix.
Yikes! So why are we so concerned about whether we choose additive or subtractive?
Some of it has to do with headroom limitations of certain software or hardware. Some of it has to do with which technique works best as a solution to a given problem. Some of it has to do with what the popular “secret technique” is this week.
While all of those are good points, sometimes the concern over which is better is a complete waste of time and energy that you could be using to get a better mix instead of worrying about technical things you might have a hard time wrapping your head around.
As the saying goes, “if it sounds right, it’s right!” Don’t stress over it.
Summing Up — Best Practices
1. Wider bandwidth—or “Q”—usually works better for additive EQ.
2. Narrower bandwidth—or “Q”—usually works better for subtractive EQ.
3. Attempting to evenly balance subtractive with additive EQ will help prevent false positive results, and still allow mixing to be fun—gaining the best of both techniques.
4. Regardless of which technique you choose, if you get something that sounds good, it’s right. Never apply a process for the sake of doing it.
Tomorrow I will discuss what kinds of EQ’s you might want to use for additive EQ, and what kind of EQ’s you might want to use for subtractive EQ, and why. To read that article, click here.