Audio & Gear • 9 min read

The Physics of Guitar Tuning, Intonation & Alternate Tunings

From YIN Autocorrelation Pitch Detection to Tempered Tuning, DADGAD, and Drop D

Executive Summary

Understand the acoustic science behind guitar pitch, why equal temperament is a mathematical compromise, how sub-cent digital autocorrelation algorithms detect pitch, and how to utilize alternate tunings like DADGAD, Open G, and Drop D.

1. The Mathematics of Equal Temperament

Guitars utilize 12-Tone Equal Temperament (12-TET), which divides an octave into 12 semitones using a frequency multiplier of 2^1/12 ≈ 1.05946.

While 12-TET allows a guitar to play in all 12 keys without retuning, pure acoustic third intervals are approximately 14 cents sharper than pure mathematical harmonics. Understanding this explains why your B string can sometimes sound slightly sharp in certain open chords even when your electronic tuner shows perfect green.

2. How the YIN Algorithm Detects Pitch

DailyFret utilizes the YIN algorithm—a specialized time-domain autocorrelation DSP technique that tracks acoustic pitch with sub-cent precision (< 0.1 Hz error). By subtracting audio phase offsets and applying parabolic interpolation, it accurately isolates fundamental guitar string frequencies while filtering out room noise and pick-strike transients.

3. Essential Alternate Tunings Matrix

Tuning NameString Notes (6 to 1)Genre / VibeNotable Songs / Uses
Standard EE - A - D - G - B - EUniversal BaselineAll genres
Drop DD - A - D - G - B - ERock / Heavy Metal / FolkOne-finger power chords, deep low-end rumble
DADGADD - A - D - G - A - DCeltic / Fingerstyle / Jimmy PageLush modal drones with open string ringing
Open GD - G - D - G - B - DBlues / Keith RichardsStrumming open major chord without fretting
Half Step Down (E♭)E♭ - A♭ - D♭ - G♭ - B♭ - E♭Hendrix, SRV, Guns N' RosesWarmer string tone, easier bends

Alternate tunings rearrange the fretboard, so re-anchor your note knowledge afterward with Memorize Every Note on the Guitar & Bass Fretboard.

Interactive Studio Tool

Put This Theory Into Daily Practice

Launch our interactive WebAudio fretboard tools to practice these concepts in real-time.

Open High-Precision Chromatic Tuner →

Frequently Asked Questions

Q: What is intonation on a guitar?

A: Intonation refers to whether notes stay in tune as you move up the neck. If your 12th-fret fretted note matches the 12th-fret natural harmonic, your guitar has proper intonation.

Published by John (Creator of DailyFret & Guitarist) • Last updated: 2026-08-20

Home Workout Chords Progressions Scales Riffs Drums Theory Guides About Us Privacy Policy Contact