Why can't you tune your guitar? (2019)

Math vs mojo: your guitar won’t be “perfectly” in tune—and players are fine with it

TLDR: Perfect tuning is impossible because guitar strings create overlapping pitches and our standard tuning system is a compromise. The crowd split between “music isn’t math” purists and nerds defending equal temperament, with calls to retune per song and jokes about tuning to vibes.

A mathy explainer claimed your guitar can’t be perfectly tuned because strings make lots of hidden pitches (harmonics), and prime-number math means some notes never lock together. Enter the crowd: Team Mojo vs Team Math. One veteran chimed in with zen wisdom: noticing you can’t get every string perfect is the moment you level up (sgarrity). Another fired back, “Absurd”—if your guitar’s within tolerance, it’s in tune, stop worshipping lab numbers (52-6F-62). Cue the engineers vs artists cage match. Then a banjo cameo: a link to Alison Brown’s harmonic “bell” trick turned the thread into show-and-tell (video), proving that those ghost notes are part of the magic. The hottest philosophical fight? 12-tone equal temperament (the modern standard that slices an octave into 12 equal steps). It’s a compromise: every chord is slightly off, equally, so nothing is perfect—and nothing is awful. amelius asked the flamethrower question: why not tune to the actual notes in a song and ditch the one-size-fits-all? xandrius pushed for receipts, demanding the “Absurd” take be explained, while commenters joked about “tuning to vibes,” “prime numbers ruining C major,” and tuners that read “¯_(ツ)_/¯.” The consensus? The math explains the mess—but musicians turn that mess into music.

Key Points

  • Perfect tuning is limited by mathematical constraints—harmonic frequency ratios do not divide evenly.
  • Pitch corresponds to a string’s vibration frequency, measured in hertz; A4 is standardized at 440 Hz.
  • A plucked string produces multiple frequencies simultaneously due to harmonics (overtones/partials).
  • Harmonics can be isolated by lightly touching the string at fractional points (1/2, 1/3, 1/4), which suppresses other modes.
  • Octaves reflect a 2:1 frequency ratio; this and other harmonic relationships underpin Western tuning practices.

Hottest takes

"My first guitar teacher told me that someday I'd start to notice that you can't get all strings perfectly in tune" — sgarrity
"Absurd. A guitar within tolerance is in tune" — 52-6F-62
"Can't we have a system that is optimized for the notes that are actually played in a song" — amelius
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