EQing in Octaves: Part 1
This is the first of a three-part email series designed to simplify your approach to EQ and help you make better mixing decisions.
We measure sound frequencies on a logarithmic scale in Hertz (Hz), or cycles per second. While essential for describing audio, this unit can feel abstract and disconnected to how we think about and create music. For example, a frequency of 100 Hz means a sound wave vibrates or oscillates for one full cycle at 100 times per second.
This is the first of a three-part email series designed to simplify your approach to EQ and help you make better mixing decisions.
We measure sound frequencies on a logarithmic scale in Hertz (Hz), or cycles per second. While essential for describing audio, this unit can feel abstract and disconnected to how we think about and create music. For example, a frequency of 100 Hz means a sound wave vibrates or oscillates for one full cycle at 100 times per second.
Musical notes are sound waves oscillating at specific cycles per second, and an octave is simply doubling or halving those oscillations to move up or down the scale.
Here’s where it gets tricky: there are only 12 notes in an octave, regardless of whether you're looking at 30–60 Hz or 3,000–6,000 Hz. This is because octaves follow a logarithmic scale—frequencies double with each octave (e.g., 20 Hz, 40 Hz, 80 Hz, 160 Hz, and so on)
This doubling can seem daunting, especially on an EQ graph, but understanding it can simplify how you approach EQing and balancing a mix.
Simplifying EQ: From Hertz to Octaves
The human ear picks up frequencies from 20 Hz to 20,000 Hz—a pretty wide range. But sound doesn’t stop at the limits of our hearing range. There are sound waves below what we can hear (infrasonic) and above it (ultrasonic). However, these low frequencies are usually filtered out by DC filters, and high frequencies by anti-aliasing filters, depending on the sample rate, of course.
Focusing on what we can hear, if we think in terms of musical octaves instead of raw numbers, that big range of 20 Hz to 20,000 Hz boils down to just under 10 octaves. That’s 10 manageable “bands” to work with, instead of 20,000 individual frequencies. Much easier to wrap your head around, right? Those 10 octaves can be broken down like this...
The 'middle' frequency of our hearing range, numerically speaking, is around 640 Hz—an unexpected midpoint, but it makes sense when we think in terms of octaves. There are about 5 octaves below 640 Hz (down to 20 Hz) and 5 above (up to 20 kHz), meaning our hearing is split evenly in terms of octaves.
Relating EQ to musical octaves makes frequency adjustments feel more intuitive and grounded in how we naturally think about music. When EQing, I typically cut with narrower bands, often about an octave wide, to address specific issues. On the other hand, when boosting, I prefer using wider bells, spanning two or more octaves, to shape the tone more musically.
However, not all octaves are perceived equally. Our ears are most sensitive to the 1–5 kHz range (roughly octaves 6–8 on the frequency spectrum), where our hearing is naturally tuned to detect detail—an evolutionary trait that likely developed for survival. This range encompasses the majority of human speech, and our sensitivity to subtle nuances within it has been essential for communication and fostering social bonds throughout history.
That may be a bit too much evolutionary context for this conversation about EQing your mix, but this 2.5-octave range demands our attention. Our ears are particularly attuned to this area and are highly sensitive to imbalance, excessive transients, and shifts in loudness. Getting it right can dramatically affect how the listener perceives loudness, balance, and presence in your mix.
Thinking in octaves can transform your approach to EQ, shifting it from a technical grind to a more natural, gestural, and musical process. By mastering the fundamentals of EQ, compression, and saturation, you’ll discover that many “problem-solving” tools—like resonance suppressors (e.g., Soothe 2)—are often used to address balance issues that could be resolved with better EQ techniques. While these tools have their place in specific scenarios, they are frequently overused in modern music production.
By understanding how octaves relate to the music we create, you can map your EQ decisions more effectively to the issues you hear in a mix. This empowers you to make more informed choices and reduces reliance on complex modern resonance tools, which can inadvertently introduce unwanted artifacts that often go unnoticed.
In Part 2, we’ll dive deeper into the individual frequency bands. We’ll talk about common issues, how to tackle them, and how to keep your mixes musical and balanced.
Have questions? Just hit reply, and we’ll get back to you. You can also tag us on instagram—we’re always happy to connect!
Be well,
Ryan Schwabe
Grammy-nominated and multi-platinum mixing & mastering engineer
Founder of Schwabe Digital
EQing in Octaves: Part 2
Last week, we explored how thinking in octaves can simplify your EQ process, making it feel more musical and intuitive. Today, we’ll take that concept further by dividing the 10 octaves into 5 key frequency bands—low, low-mids, mids, high-mids, and highs—and discussing how each band shapes our perception of sound. This week, we’ll focus on the first three bands and cover the remaining ones next week. Conveniently, each of the 5 bands spans roughly two octaves. Let’s explore them.
Last week, we explored how thinking in octaves can simplify your EQ process, making it feel more musical and intuitive. Today, we’ll take that concept further by dividing the 10 octaves into 5 key frequency bands—low, low-mids, mids, high-mids, and highs—and discussing how each band shapes our perception of sound. This week, we’ll focus on the first three bands and cover the remaining ones next week. Conveniently, each of the 5 bands spans roughly two octaves. Let’s explore them.
Lows: Octaves 1 & 2 (20–100 Hz)
As mentioned, the lowest frequency we can hear is 20 Hz. The lowest musical note we can hear is a low E, one octave below the E on an electric bass, at 20.6 Hz. This means the two low-frequency octaves range from 20 Hz to about 80 Hz. However, in practice, each band spans roughly 2.5 octaves, with some overlap between what is considered a low band and a low-mid band, or a high-mid band and a high band. In practice, the low band is commonly defined as 20 Hz to 100 Hz.
Let’s take a closer look at the low band and its role in most popular music. As you can imagine, in rhythm-section-oriented popular music, the kick and bass dominate the fundamentals of this band. I like to think of it as the foundation on which a balanced mix is built.
One approach I sometimes use is to solo the kick, bass, and vocal to evaluate how the power of the low end balances with the energy of the vocal. It’s a quick and effective way to judge the level relationship between two fundamental parts of modern music: the power of the bass and the diction as well as the message of the vocal. This method serves as a great temperature gauge, helping you reassess vocal effects, the relationship between low-frequency instruments, and how much space is left for the rest of the instruments to fit cohesively into the mix. While I am often skeptical of making any major decisions about a mix while in solo, listening to an acapella and bass has provided me with useful perspective.
The graph below shows the average spectral balance of #1 hits in the US and UK from 1950 to 2010 (AES, 2013).
In most popular music mixes, low frequencies dominate the spectrum due to the interaction between the bass and kick. The frequency balance in these #1 hits is anchored by energy centered around 80 Hz, with a sharp roll-off below 60 Hz. Higher in the spectrum, the balance follows a linearly decaying slope of approximately 5 dB per octave between 100 Hz and 4 kHz, with progressively steeper attenuation at higher frequencies. The balanced power of the low frequencies plays a crucial role in your limiter's performance, the perceived loudness of your track, and the dynamic response of your mix on consumer playback systems.
Many streaming services use K-weighted filtering (part of LUFS measurements) to mimic how our ears perceive loudness, focusing on frequencies where human hearing is most sensitive. This filtering de-emphasizes deep sub-bass frequencies, allowing producers to push sub-bass louder without significantly increasing the impact of volume normalization on a track’s loudness on streaming platforms. However, excessive deep low-end can compromise a limiter's ability to make a master sound loud and present before loudness normalization, making it a delicate balancing act to set the right amount of low-end energy.
Key Tips
Focus on dialing in the relationship between your kick and bass within the first and second octaves. Typically, the kick will dominate one octave while the bass occupies the other. Which octave each instrument primarily occupies depends on the production style and the song itself.
Adjust the low end in relation to the rest of the mix by using a low-frequency shelf that evenly boosts or cuts both low-frequency octaves.
Cut sub-bass frequencies below 25 Hz to clear up your mix and increase headroom. I prefer using low-frequency shelves over high-pass filters (HPFs) because they are more transparent and avoid phase shifts or added harmonics. Even though K-weighted filtering discounts low frequencies, these still consume the most energy in your mix and can cause unpleasant artifacts in your limiter, especially in over-compressed masters.
For a deeper dive, check out my low-end balancing blog post linked below. In that article, I outline a simple three-band strategy for managing low frequencies in your mix.
Low-Mids: Octaves 3 and 4 (100–400 Hz)
The low-mids are where the fundamentals of chords and melodies, the body of drums, and the chest of a vocal performance reside. Since the fundamentals of most instruments and vocals often live here, it’s easy for frequencies in this range to pile up. Be cautious, though—cutting too much in the low-mids can make a mix feel overly scooped and lacking in body or wholeness.
When I refer to the 'fundamental' of an instrument, I’m talking about the primary notes that make up a chord. For example, on a piano, A440 (440 Hz) is the fundamental frequency of the root note in an A minor chord. The minor third, C, is at 523.25 Hz, and the perfect fifth, E, is at 659.26 Hz. When you examine this chord on a spectrogram, you’ll see that the fundamental frequencies dominate the energy. In contrast, the subharmonics below and the harmonics above—which shape the timbre of the sound—contribute significantly less energy.
A common production mistake is stacking too many instruments in the same frequency range. When chords and instruments with fundamentals in the same range are layered, it can cause a significant buildup of density and loudness in the low-mids relative to the rest of the mix. This is why songs with fewer layers of instruments often result in a louder and clearer final master. With less low-mid frequency duplication and buildup, the energy of the production feels more balanced and open.
This is also why many producers and mix engineers embrace the concept of “production through reduction.” Simplifying and minimizing the arrangement of instruments occupying the fundamental frequencies allows each element to breathe, aligning with the human ear's preference for fewer competing elements at once.
Instead of boosting the top end to make an instrument sound brighter, try cutting in this range and raising the instrument’s overall volume. This approach preserves the integrity of the high frequencies, avoiding any potential artifacts from processing, while simultaneously reducing weight in the low mids. With this method, you’ll often achieve a cleaner and more natural result.
Exploring Alternative EQ Approaches
Similarly, I’ve experimented with working in powers of 10 instead of the traditional octave-based system we are currently discussing. While octaves function by doubling or halving a frequency, this approach involves making strategic adjustments at frequencies related by factors of 10.
For example:
To make 2 kHz feel more energetic, cut at 200 Hz and raise the volume.
To make a mix feel warmer around 400 Hz, use a wide bell cut at 4 kHz and raise the volume.
This approach is effective because it indirectly alters the balance and perceived energy of a target frequency without applying any processing to it.
Mids: Octaves 5 and 6 (400 Hz – 1.5 kHz)
The midrange, traditionally spanning 500 Hz to 2 kHz, is where the core frequencies of most instruments converge, making it the area where EQ adjustments have the greatest impact on an instrument's size and presence. The upper midrange, aligned with the Fletcher-Munson curve, corresponds to the frequencies where our ears are most sensitive—earning it the reputation as the 'size control' for a mix.
Frequency masking often occurs in this range, and pushing the mids too far forward can make instruments feel overly aggressive or 'shouty.' Additionally, overemphasizing the mids can lead to issues with loudness normalization, causing your mix to sound smaller compared to others.
For example, a gentle, wide boost around 1 kHz can help a vocal stand out, while cutting a competing instrument in the same range can unmask the vocal. If you push this range beyond a natural balance, it will cause loudness measurements to register the mix as louder, resulting in lower playback levels.
Practical Application
For Larger Vocals: Boost with a wide bell around 1kHz or 1.5kHz. Think of this as a size knob for anything in your mix. If you want something to feel bigger (and it’s not overly compressed), boost here, and it’ll grow.
For mastering, use mid-side EQ to push the vocal forward or pull it back. Solo the mid channel and sweep through the frequencies to identify the spot where the vocal stands out most relative to the other instruments. This range might not always be where you'd expect. Focus not on the vocal's fundamental frequency but on the range where it feels most separated or independent from the other sounds in the arrangement. Once you find it, adjust the gain in that range to subtly change the vocal's placement in the mix.
The lows, low-mids, and mids form the backbone of your mix, shaping its depth and power, warmth, and overall presence.
Next post, we’ll dive into the high-mids and highs—where clarity and energy live. These ranges can bring your mix to life or make it harsh if not handled carefully. See you then!
Have questions? Just hit reply, and we’ll get back to you. You can also tag us on instagram—we’re always happy to connect!
Be well,
Ryan Schwabe
Grammy-nominated and multi-platinum mixing & mastering engineer
Founder of Schwabe Digital
EQing in Octaves: Part 3
Last week, we explored the lows and mids—the fundamental frequencies that give your mix its weight, warmth, and power. Today, we'll focus on the high-mids and highs, where brightness and articulation live. These frequencies are crucial for bringing excitement and clarity to your mix, but they require precise placement to avoid harshness. Let's talk about how to craft a top end that's clear, balanced, and musical.
Last week, we explored the lows and mids—the fundamental frequencies that give your mix its weight, warmth, and power. Today, we'll focus on the high-mids and highs, where brightness and articulation live. These frequencies are crucial for bringing excitement and clarity to your mix, but they require precise placement to avoid harshness. Let's talk about how to craft a top end that's clear, balanced, and musical.
High-Mids: Octaves 7 and 8 (1.5–6 kHz)
Our ears are remarkably sensitive to frequencies in the high-mids—a trait rooted in evolution. This range, where the human voice naturally resonates, is critical for speech intelligibility and the brightness we associate with clarity in music. Our ears are finely tuned to pick up the most detail in this range—not by chance, but because it’s how we’ve evolved to communicate and survive in groups.
If your mix sounds harsh, piercing, or fatiguing, the high-mids between 2 kHz and 8 kHz are often to blame. Elements in this range can easily turn an engaging mix into an exhausting one if they’re too prominent.
For example, an overly pokey attack time on a compressor applied to an instrument in this range can push it too far forward, making it irritating. On the other hand, overusing a resonant suppressor like Soothe2 and stripping away too much transient detail can leave your mix sounding distant, dull and lifeless.
It’s not just the loudness in this frequency range that matters—it’s also the shape and intensity of the transients. Psychoacoustically, our ear associates transients in this range with something near or approaching—something potentially dangerous—so it demands our attention. A lack of transients, on the other hand, signals distance.
This response is hardwired into us—an instinctive reaction shaped by evolution to help us survive and detect threats. These same principles apply to mix depth. Reducing mids and transients creates a sense of distance and lowers attention, while boosting them brings elements forward, increasing perceived closeness and focus.
Key Tips:
If your mix feels harsh or fatiguing, check the high-mids (2–8 kHz). Use subtle EQ cuts to tame resonances without killing clarity. Balance is the goal—not dullness. Avoid excessive tight cuts to prevent phase smearing.
The transient shape in this range influences both the perceived loudness and the depth of a sound in the mix, determining whether it sits forward or further back. Sudden transient bursts push sounds forward and draw our attention, but they can also cause ear fatigue. Excessive transient control, on the other hand, pushes sounds backward and can make a mix feel distant and lifeless. These are the extremes—explore them, but don’t ignore the middle ground.
How you shape transients with compression, saturation, and distortion is crucial for defining both loudness and front-to-back placement of instruments in the mix.
Highs: Octaves 9 and 10 (6–20 kHz)
The highest octave in a mix is where air and overtones live. It’s not about distinct musical notes but rather the harmonic definition that gives sounds their sense of openness and space. This is where cymbals shimmer, vocal articulations like 'esses' and 'Ts' cut through, and instrument textures come alive.
Personally, I find that frequencies above 17 kHz often sound harsh in digital recordings—maybe a hot take, but it’s been a consistent observation. For example, I frequently use a low-pass filter on vocals between 13–18 kHz to tame distracting or overly bright frequencies. The SSL 9000 LPF is great for this.
However, if you ask a seasoned engineer, they might disagree because they historically used tubes and tape, which naturally softened and compressed these frequencies.
Quick bursts of energy in the highest octave can be especially fatiguing. Our ears enjoy brightness but recoil from excessive dynamics and resonance in the high-end. It’s not just about volume—it’s about the shape of those frequencies. Sudden boosts in the lows, like sub-bass, feel powerful and satisfying. But sudden spikes in the highs? They pierce our ears, triggering discomfort and alarm.
Managing the dynamics of this range is key to creating a mix that’s bright and open without being harsh. When balanced correctly, the highest octave can make a mix feel expansive and alive, as if it’s breathing—but overdo it, and the mix can quickly become brittle or fatiguing.
Key Tips
Sudden bursts in the highs—like an uncontrolled 'ess' or harsh cymbal—can be piercing. Start by adjusting their intensity with shelves or a low-pass filter. If the top end is too dynamic, use de-essers, tape emulations, or dynamic EQ to tame the peaks, adjusting attack time carefully. Don’t shave the transients off—right-size them for the mix. Our next plugin HiFAL is built for this, giving you effortless control over high-frequency transients.
Selective boosts around 8 kHz help vocals and lead instruments pop forward in the mix. This frequency adds presence while remaining musically connected, unlike the more airy "sizzle" of 12 kHz and above. Keep the boost subtle to avoid harshness or excessive brightness. While your instinct might be to make things brighter, sometimes reducing density in the low-mids and dynamically controlling the highs is a more effective way to achieve clarity and balance. Again, the transient shape and dynamics are as important as the level.
Making EQ Decisions That Matter
Thinking in octaves can simplify your EQ workflow, making it feel more musical and less like a technical chore. Instead of getting bogged down in the specifics of thousands of Hertz, simplify your approach with 10 octaves: use wide bells (1 octave or more) to boost and add character, and narrow bells (1 octave or slightly less) to clean up problem frequencies.
In an era of tools like Pro-Q4 and Soothe2, sleek interfaces can lead us to overthink and fix problems that don’t need fixing. While these tools are valuable, mixing and mastering are often simpler than we make them out to be. If your EQ moves start resembling a science experiment, you’ve likely gone too far.
Keep it simple—think in octaves and approach EQ with intent. This mindset aligns technical choices with musical goals, making EQ decisions feel more gestural and intuitive. Also, remember that transient intensity and shape play a major role in how we perceive harshness.
Thats it for now. In the next email, I'll discuss how tweaking our listening environment to balance perceptual bias can help us create mixes that translate across different playback systems.
Have questions? Just hit reply, and we’ll get back to you. You can also tag us on instagram—we’re always happy to connect!
Be well,
Ryan Schwabe
Grammy-nominated and multi-platinum mixing & mastering engineer
Founder of Schwabe Digital