Quick Abstract: Explored the core concepts of subtractive synthesis using a step-by-step walkthrough of oscillators, harmonics, filters, and envelopes. Demonstrated synthesis concepts with both software synths (Alchemy) and hardware (Korg Volca series). Transitioned into critical mixing fundamentals: the Fletcher-Munson curve, loudness perception, and why everything sounds better when it's louder. Introduced LUFS metering as the solution for objective loudness measurement and proper reference track comparison.
Pinned Notes
- Nathan: "Reference tracks are like — I'll sing their praises to the end of time"
- Nathan: "Get your system so that you know what an Apple sounds like" — find consistent monitoring levels for reliable mix decisions
Class Recap
Tonight we dove deep into two fundamental areas that every producer needs to master: synthesis and loudness perception. We started by deconstructing a synthesizer to understand the building blocks — oscillators generating different waveforms (triangle, sawtooth, square), filters subtracting harmonics, and envelopes shaping the sound over time. Nathan walked through the signal flow step by step, showing how triangle and pulse waves contain only odd harmonics while sawtooth waves are "buzzier" with more harmonic content.
The hardware discussion centered on the Korg Volca series, particularly the Bass and Keys models. Nathan demonstrated how these compact synths offer the same fundamental synthesis concepts but in a more musical, tactile interface compared to complex software like Logic's Alchemy.
The second half addressed a crucial mixing reality: loudness perception and the Fletcher-Munson curve. We discovered that human hearing is far from linear — we need significantly more low-end boost at quiet levels to hear bass frequencies clearly. This means when you turn up your mix, you're essentially EQing it differently.
The solution is LUFS (Loudness Units Full Scale) metering, which measures perceived loudness rather than just peak levels. Using tools like the free Youlean loudness meter, we practiced measuring songs and level-matching them for proper A/B comparisons. This transforms mixing from "hope mixing" (randomly tweaking until something sounds better) into problem-solving (identifying specific differences between your mix and professional references).
Detailed Breakdown
Synthesis Fundamentals — The basic signal path: oscillator → filter → envelope → output. We identified the key components:
- Oscillators: Multiple waveforms (triangle, sawtooth, square, pulse)
- Harmonic content: Triangle and pulse waves contain only odd harmonics, creating less "buzzy" sounds compared to sawtooth
- Filtering: The frequency parameter (cutoff) determines which harmonics get removed
- Resonance: Adds emphasis at the cutoff frequency, creating a whistle-like quality
- Envelopes (ADSR): Attack, Decay, Sustain, Release shape the sound over time
Hardware vs. Software Philosophy — While software synths like Alchemy offer unlimited routing possibilities, hardware units like the Volca provide focused, musical interfaces. Specific models discussed:
- Bass: Nathan's favorite, praised for its analog satisfaction and prominent cutoff control
- Keys: The "sleeper" that grows on users over time
- FM: Uses frequency modulation synthesis, requiring different conceptual knowledge
- Sample: Allows loading custom samples for unique sound design
- Drum: Excellent for unconventional percussion and IDM-style beats
The Loudness Perception Problem — Nathan introduced the McGurk effect video — demonstrating how visual input can change what we hear even when the audio remains constant. The Fletcher-Munson curve (Equal Loudness Contour) reveals that human hearing is extremely uneven across frequencies, and this unevenness changes with volume levels. At quiet levels, we barely hear low and high frequencies. As volume increases, we naturally hear more bass and treble. This creates the fundamental mixing challenge: when you change your monitoring level, you're effectively changing the EQ of your mix.
LUFS Metering — LUFS measures how loud something actually sounds to human ears by weighting different frequencies based on hearing sensitivity, ignoring silent passages, and calculating averages over time. The critical insight: LUFS numbers correspond directly to fader positions. If one song measures –6 LUFS and another measures –12 LUFS, you can turn down the first song by exactly 6dB to match.
Reference Track Application — Nathan demonstrated the workflow using two reggae songs with very different production styles. Initial playback suggested one sounded much "better," but LUFS measurement revealed it was simply 5–6dB louder. After level-matching, the comparison became much more revealing about actual mix differences rather than volume differences.
Key Concepts
- Subtractive synthesis: Starting with harmonically rich waveforms and filtering them
- Oscillator types: Triangle (soft, odd harmonics), sawtooth (bright, all harmonics), square/pulse (hollow, odd harmonics)
- ADSR envelope: Attack, Decay, Sustain, Release parameters shaping sound over time
- Fletcher-Munson curve: Human hearing's uneven frequency response that changes with volume
- LUFS metering: Perceptual loudness measurement that enables objective comparison
- Reference track methodology: Level-matching professional songs for meaningful mix analysis
- Monitoring discipline: Maintaining consistent levels for reliable mix decisions
Notable Quotes
- "There is this idea that the signal chain ends at the speakers… but it doesn't end with the speakers, it ends at your ear… and perception"
- "10 out of 10 people. If you play them the same thing, and play one a little bit louder, they're gonna like the louder one better"
- "You can't just turn it up. When you turn it up, you're changing the way it sounds"
- "That volume control… is the sauce. This is the most impactful thing"
Action Items
- Download and install Youlean loudness meter (free) for Ableton, or use Logic's built-in loudness meter
- Gather 3–5 reference tracks in similar styles to current projects
- Establish consistent monitoring levels in your mixing environment
- Practice measuring reference tracks and level-matching using LUFS readings
- Set up LUFS metering on master bus for objective loudness measurement
- Begin implementing reference track workflow in current mixing projects
