EMP Mixing – Week 04: EQ
Recap: Fletcher-Munson Curves & Equalization Contour
Fletcher-Munson Curves: Also known as equal-loudness contours, these curves illustrate the sensitivity of the human ear to different frequencies at various loudness levels. The curves show that we perceive midrange frequencies (around 1-5 kHz) as louder compared to very low (bass) or very high (treble) frequencies, particularly at lower volumes. This is important in music production and mixing because it helps us understand how different frequencies will be perceived at various playback volumes. For example, a mix that sounds well-balanced at high volume may lack bass and treble when played back at a lower volume, leading to the need for adjustments.
Equalization Contour: This term refers to the shape of the frequency adjustments made using an EQ. By boosting or cutting specific frequencies, you create a particular tone or “contour” in the sound. For example, the “smile curve” is a common EQ shape that boosts the low and high frequencies while reducing the midrange, often used to give a track a more pleasant and dynamic feel. Understanding EQ contours helps in making strategic adjustments to improve the clarity and tonal balance of your mix.
SEMINAR: Deep Dive into EQ and Its Application in Mixing
Introduction to EQ
We’ll start with a comprehensive look at what EQ is and why it is a fundamental tool in both corrective and creative sound shaping. Learn how EQ helps balance frequency content in a mix and resolve clashing elements for clarity.
Types of EQs
Frequency Ranges Recap
Understanding the frequency spectrum is crucial for EQ. Each range plays a unique role in a mix:
- Sub-Bass (20 Hz – 60 Hz): Adds deep rumble, typically in bass-heavy genres. Excess can cause muddiness.
- Bass (60 Hz – 250 Hz): Provides body and warmth, present in kick drums and bass instruments. Cut these frequencies in non-bass elements to reduce low-end clutter.
- Low Mids (250 Hz – 500 Hz): Adds body to instruments but can also introduce muddiness if overemphasized.
- Midrange (500 Hz – 2 kHz): Important for the clarity and presence of vocals, guitars, and most instruments.
- High Mids (2 kHz – 6 kHz): Provides attack and definition to percussive elements and vocals but too much can lead to harshness.
- High Frequencies (6 kHz – 20 kHz): Adds air, brightness, and sparkle to the mix. Too much can cause sibilance in vocals.
EQ in Context: Understanding and Tackling Frequency Masking
In music production, frequency masking occurs when two or more instruments occupy the same frequency range, causing them to clash or obscure each other. This can result in a muddy, unclear mix where individual elements lose their distinct presence. Understanding how to identify and address frequency masking is crucial for creating a balanced and polished mix.
Common Areas of Frequency Masking
Here are some of the most common regions where frequency masking tends to happen:
- Low-End Masking: Kick drums and basslines often compete for space in the sub-bass and bass frequencies (20 Hz – 250 Hz).
- Midrange Masking: Vocals, guitars, keyboards, and snare drums can clash in the midrange (500 Hz – 2 kHz), where most of the clarity and presence of a mix lies.
- High-Frequency Masking: Elements like cymbals, hi-hats, and airy vocals may overlap in the high-end (6 kHz and above), leading to harshness or a lack of definition.
Detecting Frequency Masking
It’s important to listen critically and use tools to detect frequency masking in your mix. You can:
- A/B Listening: Solo individual instruments to hear how they interact when played together.
- Frequency Analyzers: Use frequency analyzers to visually detect overlapping frequencies.
- Mix in Mono: Listening to your mix in mono can reveal masked frequencies that may not be as obvious in stereo.
The best Frequency Chart ever built
Techniques to Resolve Frequency Masking
1. EQ Carving (Subtractive Equalization)
EQ carving involves selectively reducing (cutting) specific frequencies in one instrument to create space for another. By identifying the conflicting frequency ranges, you can attenuate them in one track, allowing the other instrument to stand out.
Example: If both the kick drum and bass guitar are prominent around 100 Hz, reduce the bass guitar’s gain at 100 Hz to let the kick drum punch through.
2. High-Pass and Low-Pass Filtering
High-pass filters remove low frequencies from instruments that don’t need them, while low-pass filters remove high frequencies. This helps in clearing unnecessary frequency content that may cause masking.
Example: Apply a high-pass filter to vocals to eliminate rumble below 80 Hz, freeing up space for the bass and kick drum.
3. Panning
Panning involves placing instruments at different positions in the stereo field (left, center, right). By spreading instruments across the stereo spectrum, you reduce the likelihood of them clashing in the same frequency space.
Example: Pan guitars slightly to the left and keyboards to the right, ensuring they don’t overlap too much in the center where the vocals usually reside.
4. Sidechain Compression
Sidechain compression uses the dynamics of one instrument to control the volume of another. Typically, a compressor is triggered by a key element (like the kick drum) to reduce the volume of a conflicting instrument (like the bass) momentarily.
Example: Use sidechain compression on the bass track, triggered by the kick drum, so the bass ducks slightly each time the kick hits, preventing frequency overlap.
5. Use of Multiband Dynamics Processing
Multiband dynamics processing allows you to apply compression, expansion, or gating to specific frequency bands independently. This targeted approach helps manage overlapping frequencies without affecting the entire signal.
Example: Apply multiband compression to tame harshness in the midrange of a vocal track without altering the low and high frequencies.
6. Dynamic EQ
Dynamic EQ combines the precision of equalization with the responsiveness of compression. It allows you to apply EQ adjustments only when certain frequency levels are exceeded, making it ideal for addressing masking that occurs intermittently.
Example: Set a dynamic EQ to reduce the 1 kHz range on a guitar track only when the vocals are present, preventing masking during those sections.
7. Transient Shaping
Transient shaping involves modifying the attack and sustain portions of a sound’s waveform. By enhancing or reducing transients, you can make certain elements stand out without altering their frequency content, thereby reducing masking.
Example: Increase the attack of a snare drum to make it more pronounced in the mix, ensuring it cuts through vocals without needing EQ adjustments.
8. Stereo Imaging
Stereo imaging refers to the placement and width of sounds within the stereo field. By adjusting the stereo width and positioning of instruments, you can create separation and reduce frequency clashes.
Example: Widen the stereo image of a synth pad while keeping the lead vocals and bass centered. This separation allows each element to occupy its own space, minimizing masking.
9. Harmonic Enhancement and Saturation
Adding harmonics to certain instruments can help them cut through the mix without needing to increase their fundamental frequencies. Saturation or harmonic enhancers can make instruments more present without causing frequency overlap.
Example: Apply subtle saturation to a snare drum to add harmonics, making it more audible in the mix without boosting its fundamental frequencies.
10. Mid/Side (M/S) Processing
Mid/Side processing involves separating the audio signal into Mid (center) and Side (stereo) components. By processing these components independently, you can enhance separation and reduce frequency masking between mono and stereo elements.
Example: Convert a stereo guitar track into Mid and Side components. Mute or reduce the Mid component of one instrument (e.g., a background vocal) to make space for another instrument (e.g., lead vocals) that remains primarily in the Mid channel. Conversely, enhance the Side component of a synth pad to occupy the stereo space without clashing with the centered lead vocals.