In the intricate realm of audio mixing, precision is the cornerstone of crafting sonic masterpieces. Enter subtractive EQ, a powerful tool that wields the art of removing unwanted frequencies to sculpt a balanced and pristine sound. Subtractive EQ is a mixing technique that every aspiring audio engineer must learn how to use and apply in their mixes in order to compete with industry-standard recordings on the market. We here at Learn Audio Production often begin every mix with Subtractive EQ before we start adding effects and dynamics control plugins.

This comprehensive guide dives into the heart of subtractive EQ, unraveling its essence and illuminating its indispensable significance in the mixing process. From understanding its purpose to exploring real-world applications, we embark on a journey to decode the transformative potential of subtractive EQ and its vital role in shaping audio perfection. Lets start learning!

Demystifying Subtractive EQ:

a. Definition of Subtractive EQ:

• Subtractive EQ involves attenuating or cutting specific frequencies from an audio signal to enhance clarity and balance. In simple terms, you are removing unwanted frequencies in your mix by lowering them using an EQ plugin. These frequency are the sh*t frequencies that do not benefit a mix.

b. Embracing Audio Precision:

• Subtractive EQ focuses on cleaning up the sonic canvas, removing unwanted elements that hinder sonic quality. By lowering or completing removing unwanted or clashing frequencies, you in turn create space for other frequencies, instruments or elements to shine through your mix. Think of it as standing in a crowded bedroom. The more furniture in the room, the less space you have to move around.

c. Equilibrium through Reduction:

• By subtracting problematic frequencies, a harmonious balance is achieved, allowing essential elements to shine. This concept took me years to understand as an audio engineer. What does tonal balance mean? How do I get all my elements in my mix to work together rather than compete for space? Understanding Subtractive EQ will help answer questions like these and make you a better audio engineer, producer and mixer over time.

The Role of Subtractive EQ in Practical Terms:

a. Targeting Unwanted Frequencies:

• Subtractive EQ tends to target frequencies that cause muddiness, harshness, or masking within a mix. Depending on the song or mix, unwanted frequencies will vary and may be difficult to find if you are not familiar with the frequency spectrum. As your career progresses you are going to here terms like mud, harsh, nasty, boomy and boxy over and over again. When you hear terms like these, know that they are talking about frequencies that typically need to be lowered or reduced to create clarity and space.

b. Enhancing Clarity:

• By eliminating competing frequencies, subtractive EQ enhances the audibility and transparency of each element. Frequency Masking is a phenomena that occurs when two instruments or elements in a mix take up the same frequency range on the frequency spectrum. For example, a guitar and a voice might sometimes take similar frequencies during a mix. You must always ask yourself, which one deserver to be louder? Which one should be priority for the listener. Along with adjusting the volume fader, you can also use Subtractive EQ to slightly duck or remove competing frequencies.

HINT: When you are first starting out, it is imperative you us a Frequency Analyzer on your master bus so you begin learning where certain instruments or elements lay on the frequency spectrum. I cannot stress this enough. You need to learn what frequency masking is, what low end build up looks and how to identity sh*tty frequencies that need to be removed or reduced in a mix.

c. Creating Space:

• Subtractive EQ clears space in the frequency spectrum, allowing each instrument to occupy its distinct sonic realm. This is primarily how we use Subtractive EQ when we are mixing in our studio. When you begin balancing all elements in a mix, for example (guitars, bass, synths, vocals, strings, backgrounds vocals & drums), they all cannot be balanced at the same level nor can they all take up the same frequencies at the same time. This will sound muddy and it will be difficult to hear each and every element in your mixes. Remember, your job as a mix engineer is to ensure your mixes translate well to the listener so that they may form an emotional connections to the music. This will not happen if you cannot hear each element in a mix, no matter how low or high in volume an instrument is.

The Importance of Subtractive EQ in the Mixing Process:

a. Addressing Overlapping Frequencies:

• When multiple instruments share similar frequencies, subtractive EQ resolves clashes, allowing each to shine. This is the never ending battle of a mix engineer. Most instruments share similar frequencies and learning how to balance them all will take years. Sorry! This is the unfortunate, or fortunate truth, depending on how you look at it. This career take time to learn and experience is so vital to your growth and skills as a mix engineer. An EQ is such a powerful tool in every DAW. Whichever DAW you are using, learn how to use its EQ plugin early on in your journey! In our experience, most mix

b. Reducing Masking:

• Subtractive EQ mitigates masking, where one instrument obscures another, leading to a more defined mix. In its simplest terms, masking is when two elements share similar frequency ranges which causes a blurring or masking of each element. You basically cannot hear what is happening almost those elements. It is very simple concept that has large implications in a mix if you do not understand how to properly balance frequencies. Take for example a piano and a guitar. If you hit the same note on each, say for example a C1, the fundamental note of both instruments will show up in the same spot on the frequency spectrum. What do you do? Do you lower the piano and higher the guitar? Do you lower the guitar and higher the piano? Do you balance them both equally then create bell curve on an EQ plugin and lower the fundamental note on the piano? As you can see things, can get out of hand really if you do not begin educating yourself on the fundamentals of audio production.

c. Achieving Balance:

• By removing unnecessary frequencies, subtractive EQ achieves a balanced sonic landscape, devoid of sonic clutter. Balance in a mix is what every audio engineer strives for when working with their own music or a clients. Not only do you have to pay attention to your volume faders during a mix session, you have to understand the balance of frequencies when applying EQ to individual elements of a song. Most novice audio engineers, seek to boost frequencies first when starting a mix. DO NOT DO THIS! Do not go boosting things like crazy on an EQ plugin before you have actively searched for frequencies to cut or remove. You will create more masking problems down the line leading to an amateur, cluttered, muddy mix that you nor your clients will enjoy, let alone the listener.

HINT: Take our advice and begin every mix by using subtractive EQ. To hear “frequency masking” easier, begin every mix in MONO. If your DAW allows it or if you need a Utility plugin, on you master buss make sure all sounds are coming out in MONO. You will begin to hear clashing frequencies right away, giving you hints on where to start when “cleaning up” your mix.

A Sequential Approach: Subtractive EQ before Additive EQ:

a. Clearing the Canvas:

• Begin with subtractive EQ to remove problematic frequencies before introducing additional elements. We’ve used this analogy before, so pay attention. Imagine you are in a single bedroom filled with a ton of furniture all staked and thrown in the middle. You will obviously have to sort through all the pieces of furniture, organize the room and even trash some of the items that don’t fit within the room. Not every item can be the focal point of the room. You need to create space! This is the exact same concept when it comes to working with the frequencies spectrum within a particular song you are mixing. Get rid of the sh*t that does not need to be there. For example but not limited to noise, low end rumble, resonant frequencies, harsh frequencies, muddy areas…the list goes on and on. Over time you will learn what these terms truly mean and will be able to identify them rather quickly. Keep practicing!

b. Preserving Audio Integrity:

• Subtractive EQ maintains the integrity of the original sound, avoiding over-processing and unnatural artifacts. Unfortunately, over-processing is something you are going to do as a novice audio engineer. Preserving audio integrity can mean multiple things. Addressing noise, lowering hiss, getting rid of unnecessary low end rumble, cutting out that darn air conditioner that is in the vocal recording, addressing any unnecessary EQ spikes. Scenarios like these will undoubtedly be a part of your journey. Surprisingly enough, most of these issues can be fixed with an EQ plugin.

HINT: It is just the reality of how this game is played. You are here for a reason! Learn as much as you can! Read as much as you can! Practice as much as you can!

c. Enhancing Efficiency:

• Starting with subtractive EQ streamlines the subsequent additive EQ process, leading to cleaner and more precise results. As explained earlier, most novice audio engineers make the mistake of boosting highs and lows to get that polished, professional sound to early on in mix process. Little do they know they are boosting all the sh*tty frequencies too, creating more problems for themselves as they fight to get every element in the mix to stand out. Imagine you were in an already crowded bedroom and decided to make all the furniture bigger for some reason. You wouldn’t have room to move about the room, let alone move things around. It is the same concept here when we are discussing efficiency and the mix process.

Real-World Scenarios and Benefits:

a. Scenario: Muddy Mix:

• Identify frequencies causing muddiness and remove them, allowing instruments to emerge with clarity. Muddy frequencies tend to live in the 100 Hz to 500 Hz range but can vary depending per song. These frequencies often cause boomy or boxy tones that are not pleasing to hear on their own and will most definitely destroy a mix if they are too overpowering. However, when starting out, do not always search for and completely remove this part of the frequency spectrum of a mix, removing too much will lead to a dull, lifeless mix. Yes. I understand I spent several paragraphs informing you about lowering or removing unwanted frequencies but tread lightly. Mixing is about balance and over processing will ruin your mix for sure.

b. Scenario: Vocal Presence:

• Subtractive EQ removes masking frequencies, enhancing vocal presence against the backdrop of instruments. One of the most effective ways to use Subtractive EQ while mixing, is when working with vocals. One of the most common ways to utilize this technique is when using a High-Pass Filter on on EQ to remove all the low-end rumble on a voice recording. Often times, vocalists cannot reproduce any notable sounds in the extreme lower register of their voice. Often times everything below 200 Hz just sounds like hot gravy and cant be used in a musical way during the mix process. So what is the answer to this problem? Get rid of it! This is just one example of the numerous ways to use a Subtractive EQ technique to help improve the sound quality of a mix.

c. Scenario: Taming Harshness:

• Eliminate harsh frequencies in instruments like cymbals or strings, transforming them into smoother elements. Harshness can be thought of as those high frequencies that make your ears bleed when you hear them. No one, and I mean no one, is capable of withstanding hearing those harsh frequencies for a long time. If your mix contains a large amount of noticeable harshness, your listener will give up on your song immediately and never return. This is where lowering them an EQ, multiband compressor or Low-Pass Filter, comes in handy.

Essential Terminology for Understanding Subtractive EQ:

a. Frequency Clashes:

• Overlapping frequency ranges between instruments that result in sonic clashes. Just remember that some instruments or elements in a mix will share the same frequency ranges. Your job as a mix engineer is to learn how to balance these ranges.

b. Masking:

• When one sound masks or hides another due to shared frequency content. If two elements are sharing the same space, how do you know what each element is. Always ask yourself when mixing, what should take priority. Not every element in a mix can be front and center. Frequency masking will lead to cluttered, muddy mixes.

c. Artifacts:

• Unintended and unnatural sounds introduced during processing. Artifacts are a part of the recording process. They are everywhere! From noise, digital clipping, unwanted distortion, equipment issues, audio interface power surges, speaker feedback, etc. The list is endless. Artifacts can often be treated with EQ too! That is why it was discussed in this article about Subtractive EQ.

In conclusion, the realm of subtractive EQ emerges as a guiding light in the quest for sonic perfection, ensuring clarity, balance, and depth within a mix. By understanding its purpose, grasping its practical applications, and embracing a sequential approach, you unravel the art of sculpting audio excellence. Whether you’re addressing frequency clashes, enhancing vocal presence, or taming harshness, subtractive EQ stands as a guardian of sonic purity, elevating your mixes to unprecedented levels of precision. So, let the symphony of sonic clarity resonate as you venture into the world of subtractive EQ, reshaping your audio creations with meticulous finesse and auditory splendor.