Chromaticism & Dissonance for Tension

The Nature of Dissonance: From Physics to Perception

Before we can effectively manipulate dissonance, it's essential to understand what it is. Your background in physics provides a unique advantage here, as the foundations of dissonance are rooted in wave mechanics and psychoacoustics.

When two or more notes are played simultaneously, their sound waves interfere. If their frequencies are very close but not identical, they produce a phenomenon called "beating"—a noticeable fluctuation in amplitude. As the frequency difference increases, these beats become faster, eventually merging into a quality we perceive as "roughness." This sensory roughness is a primary physical component of dissonance.

Furthermore, real-world sounds, like those from synthesizers, are not pure sine waves. They are complex tones composed of a fundamental frequency and a series of overtones (the harmonic series). Dissonance arises not just from the interaction of the fundamental frequencies, but from the roughness generated by all the interacting partials of the notes being played together.

The following video provides an excellent quantitative look at this phenomenon, explaining how "dissonance graphs" can be constructed to visualize the roughness between notes.

The video introduces a visual tool known as a dissonance curve, which maps the perceived dissonance against the frequency ratio of two notes.

This physical understanding forms the basis, but it's not the whole story. Our perception of dissonance is also shaped by cultural and musical context. The research paper "On Musical Dissonance" introduces a dual-process theory, arguing that our experience of dissonance is a combination of two factors:

1. Sensory Dissonance: The bottom-up psychoacoustic "roughness" we just discussed.
2. Tonal Dissonance: A top-down cognitive factor based on our learned, implicit knowledge of musical conventions. A chord is "tonally dissonant" if it violates the norms of the musical system we're accustomed to.

This dual model is crucial for us as producers. We can create tension using intervals that are inherently "rough" (like a minor second) and also by subverting harmonic expectations built through cultural learning.

A Producer's Guide to Dissonant Intervals

In many musical styles, the goal is to create tension only to resolve it. However, in techno, industrial, and related genres, the objective is often to create and sustain a high level of tension, never fully offering the comfort of resolution. This requires a different approach to harmony—one that embraces dissonance.

Let's classify intervals by their tension potential, specifically for the context of electronic music production.

To summarize, for building tension, we are most interested in:

• Minor Second (m2): A one-semitone interval (e.g., C to C#). It is highly dissonant and "grating."
• Major Seventh (M7): An eleven-semitone interval (e.g., C to B). It is also highly dissonant and creates a strong "pull" back to the octave.
• Tritone: A six-semitone interval (e.g., C to F#). Historically dubbed diabolus in musica (the devil in music), it has a famously unstable and ambiguous sound.

Building Tension in Practice: Macro vs. Micro

Tension in a track operates on multiple timescales. The resource "The Advanced Guide to Tension and Energy in Electronic Music" provides a useful framework by distinguishing between two types of tension:

• Macro-tension: Large-scale tension built over many bars, characteristic of build-ups leading into a drop or major transition. This involves layering sounds, filtering, and evolving harmony.
• Micro-tension: Small-scale tension created over short durations (e.g., one or two beats) to keep the listener engaged and the track moving forward. This includes things like short fills, reverse cymbals, and momentary harmonic dissonances.

Harmonic Techniques for Tension

Now, let's combine our understanding of dissonant intervals with the concept of musical tension. Here are specific techniques you can use to create builds and drops.

1. Chromatic Movement

Moving a melody or a chord by semitones is one of the most effective ways to build tension. This is because chromatic motion inevitably involves the highly dissonant minor second interval.

• Chromatic Risers: A classic technique where a synth line or pad chromatically ascends, often over one or two octaves, during a build-up. In the previous lesson, we called this chromatic planing.
• Chromatic Basslines: In genres like acid techno, a bassline that moves chromatically creates a relentless, hypnotic tension.
• "Wrong" Notes: Introducing a note one semitone above or below a stable chord tone creates a powerful, localized dissonance that begs for resolution. You can let it resolve for a moment of micro-tension, or leave it unresolved to build macro-tension.

2. Exploiting the Tritone: The Dominant 7th Chord

The dominant 7th chord (V7) is a cornerstone of functional harmony precisely because it contains a powerful dissonance that drives the music forward. The interval between the 3rd and the 7th of a dominant 7th chord is a tritone. For example, in a G7 chord (G-B-D-F), the interval between B and F is a tritone. This inherent instability creates a strong pull towards the tonic (I) chord.

In a build-up, you can:

• Introduce a V7 chord: If your loop is based on a simple modal progression, introducing the V7 chord will dramatically increase the tension and create the expectation of a drop.
• Repeat the V7 chord: Instead of resolving it, you can loop the V7 chord, frustrating the listener's expectation and amplifying the tension before the drop finally provides the release (or transitions to a new state of tension).

3. Suspension and Dissonant Clusters

Suspension is the technique of holding a note from a previous chord over a new chord with which it is dissonant, before resolving it.

• Example: In a C major chord (C-E-G), holding the G and then changing the underlying harmony to an F major chord (F-A-C) makes the G a dissonant suspension over the F chord. It "wants" to resolve down to F.

For building tension, you can simply not resolve the suspension. A pad holding a suspended note that never resolves throughout a build-up can create a subtle but growing sense of unease. Extending this idea, you can intentionally create dissonant clusters—chords built from adjacent notes, like C-C#-D—to create maximum sensory roughness. These are staples of noise and industrial music.

4. The Context of Dissonance

As the dual-process theory suggests, context is key. A dissonant chord can sound less tense in a logical progression, while a consonant chord can sound tense in a chaotic one. Experiment 3 in the "On Musical Dissonance" paper demonstrated this empirically:

"...chords that are readily construed as tonal sound less dissonant in tonal sequences..., whereas chords that are not construed as tonal do not differ reliably in their dissonance depending on their context."

This means you can manipulate perceived tension by controlling the harmonic context. In a build-up, you could gradually shift from a clear, repeating modal loop to a more random or chaotic sequence of chords. This breakdown of harmonic logic itself creates a powerful form of cognitive tension, even if the individual chords aren't maximally dissonant.

Conclusion

Today we've deconstructed dissonance, tracing it from the physical interference of sound waves to a powerful compositional tool for managing energy in electronic music. You now have a multi-layered understanding of how to generate and control tension.

Key Takeaways:

• Dissonance has a physical basis: Sensory dissonance, or "roughness," is caused by the beating of closely-spaced frequency components (fundamentals and overtones) in complex sounds.
• Dissonance is also cognitive: Our perception of dissonance is influenced by our learned expectations of a musical system. Violating these expectations creates "tonal dissonance."
• Intervals have a tension hierarchy: For building tension, the most potent intervals are the minor second, major seventh, and tritone.
• Chromaticism is a direct path to tension: Moving by semitones naturally incorporates the highly dissonant minor second interval, making it ideal for risers and tense melodic lines.
• Harness harmonic devices: Use dominant 7th chords for their strong pull, suspensions to create unresolved dissonance, and dissonant clusters for maximum roughness.
• Tension is a primary element of arrangement: Use these harmonic techniques to create both large-scale macro-tension (in builds) and small-scale micro-tension (to maintain interest).

For your next production session, try creating an 8-bar build-up. Start with a simple bassline and pad loop. Then, layer these techniques:

1. Introduce a chromatically ascending synth line (planing).
2. Automate a synth pad to hold a suspended note over the last 4 bars.
3. In the final bar, replace the existing harmony with a single, sustained V7 chord or a dissonant tone cluster.
4. Drop back into your original loop.

Pay close attention to how the energy and anticipation build with each added layer of harmonic tension.

In our final lesson of this module, we will apply these concepts to a genre-specific context: analyzing how harmonic ambiguity and tension are manipulated in industrial and noise music, taking your understanding of dissonance to its practical extreme.