What is PTT Tuning? Robert Edward Grant's Precise Temperament Tuning Explained

PTT (Precise Temperament Tuning) is a revolutionary musical tuning system developed by polymath Robert Edward Grant. Based on sacred geometry principles and the cuboctahedron, PTT offers a mathematically precise alternative to traditional tuning systems, featuring a unique major third ratio of 1.26 and an A4 reference frequency of 432.081216 Hz.

Understanding Musical Tuning Systems

Before diving into PTT, it's essential to understand what musical tuning systems are and why they matter. A tuning system defines the precise frequencies of musical notes and the intervals between them. Throughout history, different civilizations have developed various tuning systems, each with its own mathematical basis and sonic characteristics.

The most common tuning system today is Equal Temperament, which divides the octave into 12 equal semitones. While mathematically elegant and practical for modern instruments, some argue that Equal Temperament sacrifices the purity of certain intervals for the sake of convenience.

Who is Robert Edward Grant?

Robert Edward Grant is a polymath, researcher, and author known for his work in mathematics, sacred geometry, and alternative sciences. His research spans multiple disciplines, including:

Grant's work on PTT represents a convergence of these interests, applying geometric principles to create a musically coherent tuning system.

The Cuboctahedral Foundation of PTT

PTT is based on the cuboctahedron, a geometric solid that sits at the intersection of the cube and octahedron. This Archimedean solid has unique properties:

The cuboctahedron appears in nature at the molecular level and has been studied in various fields, from crystallography to quantum physics. Grant theorizes that this geometric structure holds keys to understanding harmonic relationships in music.

The Mathematical Basis

PTT derives its interval ratios from the geometric relationships within the cuboctahedron. The system maintains mathematical precision while creating musically consonant intervals. Unlike systems that compromise for practicality, PTT prioritizes geometric accuracy.

PTT's Unique Major Third: The 1.26 Ratio

The most distinctive feature of PTT is its major third ratio of 1.26. To understand its significance, let's compare it to other tuning systems:

Tuning System Major Third Ratio Frequency (from A=432Hz)
Equal Temperament 1.2599 (2^(4/12)) ~544.29 Hz
Just Intonation 1.25 (5/4) 540 Hz
PTT 1.26 544.42 Hz

The 1.26 ratio is slightly wider than Just Intonation's 5:4 ratio (1.25) but very close to Equal Temperament. This positioning creates a unique sonic character—retaining some of the purity of Just Intonation while maintaining the flexibility of tempered systems.

The 432.081216 Hz Reference Frequency

PTT uses A4 = 432.081216 Hz as its reference frequency, a precise value derived from geometric calculations. This is close to, but distinct from, the popular 432 Hz tuning advocated by some musicians and researchers.

Why 432 Hz Tuning?

Many musicians and researchers prefer 432 Hz over the standard 440 Hz because:

  • It's mathematically related to natural phenomena (Earth's rotation, Schumann resonance)
  • Some claim it produces a "warmer" or more "natural" sound
  • Historical instruments may have been tuned closer to 432 Hz
  • It creates whole number frequencies for C (256 Hz)

PTT's 432.081216 Hz takes this further, deriving the exact value from geometric principles rather than rounding.

Complete PTT Frequency Ratios

Here are the complete PTT ratios for all 12 chromatic notes, relative to A4:

Note PTT Ratio (relative to A) Frequency (Hz, A=432.081216)
C0.595322630257.25 Hz
C#0.630000000272.21 Hz
D0.666664800288.09 Hz
D#0.707106781 (√2÷2)305.54 Hz
E0.750000000324.06 Hz
F0.793700526343.16 Hz
F#0.840000000363.03 Hz
G0.893061020385.97 Hz
G#0.944911182408.36 Hz
A1.000000000432.08 Hz
A#1.058113883457.27 Hz
B1.125000000486.09 Hz

Notable features of these ratios:

How PTT Compares to Other Tuning Systems

PTT vs. Equal Temperament

Equal Temperament divides the octave into 12 equal semitones, with each semitone being exactly 2^(1/12) ≈ 1.05946 times the previous note. This makes modulation between keys seamless but compromises the purity of intervals.

PTT maintains certain pure intervals (like the perfect fifth at 3:2) while introducing the unique 1.26 major third. This creates a different color palette for composers while retaining mathematical elegance.

PTT vs. Just Intonation

Just Intonation uses simple whole number ratios (3:2, 5:4, 4:3, etc.) to create perfectly consonant intervals. However, this leads to practical problems when modulating between keys.

PTT borrows from Just Intonation's purity (maintaining the 3:2 fifth) but modifies other intervals to allow for greater flexibility. The 1.26 major third is close enough to Just Intonation's 5:4 to sound consonant but different enough to create a unique character.

PTT vs. Pythagorean Tuning

Pythagorean Tuning builds all intervals from stacked perfect fifths (3:2 ratios). This creates pure fifths but results in very sharp major thirds.

PTT maintains pure fifths like Pythagorean tuning but uses the 1.26 ratio for major thirds, creating a more balanced sound for harmonic music.

Experiencing PTT in Practice

The best way to understand PTT is to hear it. When you listen to music in PTT tuning, you may notice:

Try PTT Yourself

You can experience PTT tuning directly in MusiPhi, our sacred geometry music visualizer. Select "PTT A=432Hz (Robert Edward Grant)" from the tuning system dropdown and play notes on the virtual keyboard or your MIDI controller.

Compare PTT to the other 6 tuning systems available in MusiPhi to hear the differences firsthand.

Applications of PTT Tuning

Meditation and Sound Healing

The 432 Hz reference frequency and geometric ratios make PTT potentially useful for meditation music and sound healing practices. The mathematical precision may create harmonic relationships that resonate with practitioners.

Experimental Music Composition

Composers interested in alternative tuning systems can use PTT to explore new harmonic territories. The unique 1.26 major third offers a fresh palette for creating music with distinct emotional qualities.

Research and Education

PTT serves as a fascinating case study in the intersection of mathematics, geometry, and music theory. Students and researchers can examine how geometric principles translate into musical systems.

Sacred Geometry Music

For artists working with sacred geometry themes, PTT provides a tuning system that's philosophically aligned with geometric principles, creating music that's both conceptually and sonically coherent with visual geometric art.

Using PTT in Music Production

While PTT tuning isn't yet widely supported in mainstream music software, there are ways to use it:

The Future of PTT and Alternative Tunings

As interest in alternative tuning systems grows, PTT represents a modern approach to an ancient question: What makes music harmonious? By grounding tuning decisions in geometric principles, Robert Edward Grant has created a system that:

Whether PTT becomes widely adopted or remains a specialized tool for experimental musicians, it represents an important contribution to the ongoing exploration of musical tuning systems.

Conclusion

PTT (Precise Temperament Tuning) by Robert Edward Grant is a geometrically-based tuning system featuring a unique 1.26 major third ratio and a reference frequency of 432.081216 Hz. Derived from cuboctahedral geometry, PTT offers musicians and researchers an alternative to traditional tuning systems, combining mathematical precision with musical expressiveness.

The best way to understand PTT is to experience it. Try playing music in PTT tuning and comparing it to Equal Temperament, Just Intonation, and other systems. Your ears will tell you what the mathematics suggests: PTT offers a unique sonic signature that's worth exploring.

Experience PTT Tuning Now

Try Robert Edward Grant's Precise Temperament Tuning in MusiPhi's interactive visualizer. Compare PTT to 6 other tuning systems with real-time sacred geometry visualization.

Launch MusiPhi App

Further Reading

Explore more about alternative tuning systems and sacred geometry: