How SuperCollider Proved It
The computational verification of MMA’s universality — the script that tested all 66 heptachords against all chord types, and what made the proof rigorous rather than intuitive.
The claim that MMA is the only 7-note scale where all 12 transpositions function over real chords in a single key center is a mathematical claim. Mathematical claims require proof — not demonstration of a few cases but exhaustive verification of all cases. Intuition can suggest a relationship; computation can prove it. The SuperScales discovery required both: musical intuition to formulate the question, and SuperCollider and Python to answer it rigorously.
This article describes the computational verification process — how the test was formulated, how it was implemented, what the results looked like, and why the computational approach was necessary rather than optional.
Why Computation Was Necessary
The verification required testing 66 heptachords × 12 transpositions × (approximately 20 real chord types per key center) = approximately 15,840 scale-chord pairings. Each pairing required determining which scale tones were chord tones, which were tensions, and which were avoid notes relative to the specific chord type. This is a well-defined algorithmic procedure — but doing it 15,840 times by hand would take weeks and introduce human error into the process.
More fundamentally, the claim is a universal statement: “all 12 transpositions of MMA function over real chords.” Universal statements require testing all cases, not just the suggestive ones. Before computational verification, a musician might suspect that MMA had special properties — but suspicion is not proof. The computation is what converts a hypothesis into a confirmed finding.
The Python Implementation
# All 66 heptachords as pitch class arrays (prime forms) heptachords = { '7-34': [0,1,3,4,5,6,8], # MMA '7-35': [0,1,3,5,6,8,10], # Major scale # ... all 66 heptachords } def has_avoid_note(scale_pcs, chord_root, chord_quality): chord_tones = get_chord_tones(chord_root, chord_quality) tensions = get_tensions(chord_root, chord_quality) for pc in scale_pcs: if pc not in chord_tones and pc not in tensions: # Check if pc clashes with a chord tone by semitone if any(abs(pc - ct) % 12 == 1 for ct in chord_tones): return True return False def test_heptachord(forte_name, prime_form): passes = 0 for transpose in range(12): scale = [(pc + transpose) % 12 for pc in prime_form] for chord in real_chords_in_C: if not has_avoid_note(scale, chord.root, chord.quality): passes += 1 break # This transposition passes return passes == 12 # True only if ALL 12 transpositions pass
The Results
SuperCollider — Audio Confirmation
After the Python script identified MMA as the only passing heptachord, SuperCollider was used to generate audio for each of the 12 MMA transpositions — the scale played against a drone plus the corresponding chord — to confirm aurally that the mathematical result was also a musical one. This is the experimental confirmation step: the mathematical proof says it should work; the audio says it does work.
The audio confirmation step revealed something the mathematical test alone cannot capture: the quality of the pass. Some scale-chord pairings that technically have no avoid notes still sound awkward or strained — they pass the algorithm but not the ear. For MMA, every one of the 12 transpositions passed both tests — mathematically zero avoid notes, and musically coherent against the corresponding chord. The algorithm’s definition of “pass” was a reliable predictor of the musical result.
This alignment between mathematical and musical evaluation is itself meaningful. It confirms that the algorithm’s avoid-note definition captures something real about musical perception — not just an arbitrary rule but a genuine acoustic criterion. The computational proof and the auditory proof point to the same conclusion.
Computational proof and scientific method
Exhaustive enumeration
Testing all 66 heptachords is the computational equivalent of a controlled experiment — all variables held constant except the one being tested (scale type). The result is a true comparison, not a cherry-picked demonstration of the conclusion you expected.
Algorithm as theory
The avoid-note classification algorithm is a formalization of music theory — a precise, computable definition of “works over a chord.” Making the theory precise enough to compute reveals its assumptions and makes them testable. Vague theories cannot be verified; precise ones can.
Experimental confirmation
The SuperCollider audio confirmation is the experimental step — theory (Python) predicts, experiment (audio) confirms. The alignment between mathematical and auditory evaluation validates both the algorithm and the musical intuition behind it.
Universal vs. existential
“MMA works over some chords” is an existential claim — easy to demonstrate by example. “MMA works over all 12 dominant positions” is a universal claim — requires testing all cases. Computation is what makes universal claims provable rather than just plausible.
The next article examines the production of the 864 MIDI drones that accompany the SuperScales book — how one drone per mode per key was generated, what makes a good drone acoustically, and the engineering decisions behind the SuperScales drone system.
SuperCollider: supercollider.github.io. Python music21 library for pitch class set computation: web.mit.edu/music21. The verification code and full results are documented in the SuperScales book at muse-eek.com.
