Surge Synth: A Comprehensive Guide to Microtonal Tuning

This video demonstrates a 13-limit just intonation piano tuning system where Jacob Adler begins with C as the fundamental tone, tunes a Pythagorean chain of fifths (C-G-D-A), adds pure major thirds using the fifth harmonic, introduces extended harmonies through the seventh harmonic (creating crunchy C7 chords and narrow minor thirds), and incorporates the 11th and 13th harmonics for microtonal colors, enabling harmonic series up to the 16th partial.

This comprehensive exploration examines whether Renaissance singers could achieve pure harmonic intervals without temperaments. The video traces the theoretical foundations: Zarlino advocated natural pure singing, but this approach faces fundamental contradictions. Pure fifths create Pythagorean thirds too high, requiring syntonic comma adjustments for pure major and minor thirds. Three critical problems emerge: pitch migration causes drift during harmonic progressions; melodic intervals become compromised and sound alien; human performance introduces unavoidable micro-errors. Historical evidence shows no terminology or notation for just intonation's required intervals, and no traces of widespread practice exist. Singing with instruments bound to temperaments provided practical foundations, with composers like Gesualdo engaging with chromatic keyboards. Hercole Bottrigari's description of Padovan singers reveals that achieving perfect vocal union required constant refinement, resulting in 'almost celestial harmony'—demonstrating that true just intonation remained an elusive ideal rather than achievable practice.

Temperaments are systems defining interval sizes within the octave, creating pitch relationships. Equal temperament (modern piano tuning) divides the octave into 12 equal semitones, but this makes all intervals slightly impure. Two critical commas govern temperament creation: the Pythagorean Comma (~24 cents) arises when tuning perfect fifths around the Circle of Fifths and failing to return to the starting pitch; the Syntonic Comma (~22 cents) represents the difference between four pure fifths versus two octaves plus a pure major third. These fixed discrepancies must be distributed across intervals, creating an infinite number of possible temperaments. Historically favored systems balance maintaining pure intervals against enabling playability across multiple keys—a fundamental tension in tuning design.

This comprehensive exploration covers historical musical tuning systems. Equal temperament divides the octave into 12 equal semitones, enabling play in all keys but with compromised intonation. Historical temperaments like quarter comma mean tone used movable gut frets to create unequal divisions, achieving pure major thirds in specific keys like D major. However, this purity came at the cost of other keys sounding dissonant. Enharmonic notes (C sharp/D flat) are the same pitch in equal temperament but different in historical systems. Musicians used tostinos—small gut pieces on fretboards—to resolve these harmonic notes. The demonstration shows how historical temperaments create surreal, resonant sounds in compatible keys while producing painful dissonance in others, illustrating the fundamental trade-offs between intonation purity and musical flexibility.

This video demonstrates how 31-TET enables exploration of microtonal harmonies beyond traditional 12-TET. Key techniques include: (1) Augmented sixth chords approximating 4:5:6:7 just intonation ratios with a distinctive 'crunchy' sound; (2) The middle third as a distinct playable note, creating 'warbly' chord effects; (3) Wolf intervals and upper structure chords like the 3:5:7 chord; (4) The miracle decatonic scale with interval pattern 3 3 3 3 3 3 4 3 3 3; (5) Harmonic series chords (4:5:6:7:9:11:13) moving chromatically. These techniques allow musicians to access new sonic territories while maintaining connections to familiar tonal centers.

Whole tone composition employs advanced techniques including inversion (reversing melodic direction), rhythmic diminution (reducing note values while maintaining shape), and transposition (shifting patterns to new pitches). Inversion creates developmental variation by playing ideas descending after presenting them ascending. Diminution adds rhythmic interest through value reduction. Transposition generates related yet distinct material. These techniques demonstrate how conventional compositional methods remain applicable when working outside traditional harmonic conventions.

To create unique musical progressions beyond conventional I-IV-V patterns, musicians must understand musical systems and exotic scales. A tonal system is the underlying structure of music, with 99% using major or minor scales. To innovate, musicians should invent new tonal systems using exotic or artificial scales. The Neapolitan Minor Scale (C-Db-Eb-F-G-Ab-B-C) serves as an example. The key technique involves constructing triads from each scale note: C-Eb-G (Cm), Db-F-Ab (Db major), Eb-G-B (augmented), F-Ab-C (Fm), G-B-Db (major with diminished fifth), Ab-C-Eb (Ab major), and B-Db-F (sus2 b5). These unconventional chord structures create dissonant but functional harmonic systems that move beyond traditional tonal expectations.

Before the 15th century, Pythagorean tuning dominated—using pure fifths without tempering, creating a system where the circle of fifths never closes. The resulting 'wolf' interval between G-sharp and E-flat was avoided. Major thirds were extremely large (called 'ditonus') and semitones were unequal. Music composed in this system used pure intervals (octaves and fifths) in openings and impure thirds/sixths in cadences to create tension and resolution. The transition to meantone temperaments in the 16th century allowed purer thirds at the cost of more impure fifths.

Musical tuning systems determine how notes are arranged on instruments. Standard tuning is E-A-D-G-B-E, but alternative tunings like Drop D or Drop C are common in metal music. These tunings enable easier power chord shapes and deeper resonant tones. Harmonic techniques like natural harmonics create clean, bell-like sounds that add texture to music. Understanding tuning and harmonics allows musicians to create unique sounds and explore different musical possibilities.

A global tuning system allows music producers to create and manipulate custom tuning systems across all tracks in a project, enabling exploration of microtonal scales like 7 EDO or 31 EDO, and facilitating dynamic modulation of tuning parameters over time to create unique musical interpretations.

This section explains how MPE (MIDI Polyphonic Expression) technology enables expressive microtonal performance. Unlike standard MIDI which treats all notes uniformly, MPE allows independent pitch bending and pressure control for each note in a chord. By combining MPE with microtuner, producers can pitch-shift individual notes to match microtonal scales while maintaining expressive control. This integration transforms static microtonal tunings into dynamic, evolving soundscapes where each note can be manipulated independently, opening possibilities for performance techniques impossible with traditional synthesizers.

MPE enables each pad to produce different sounds based on horizontal (pitch) and vertical (timbre) movement. The device includes a 'finger' positioning feature that adjusts the pitch center point, allowing pressing anywhere on the pad to produce correct pitch. This enables more humanized and natural sound expression, eliminating the mechanical feel of traditional MIDI controllers where each key produces identical sounds.

Beyond MIDI-to-CV conversion, MicroTune functions as a quantizer for continuous CV signals by configuring automatic gate triggering and sample-and-hold circuits, forcing signals into discrete scale steps. MPE (MIDI Polyphonic Expression) implementation requires assigning each voice to separate MIDI channels and routing pressure data accordingly, enabling independent pitch bend and timbre control for each note. Microtuning is an integral part of the original MIDI protocol, with System Exclusive messages designed specifically for communicating tuning data to compatible synthesizers. This enables seamless integration between DAWs and hardware for microtonal composition.