Back to blog
temperament theory

Why Equal Temperament Isn't Enough

David Ehlers / / Updated

Every fretted instrument you’ve ever played is tuned to equal temperament. It’s the default, the standard, the unquestioned norm. And it’s a compromise that makes every interval — except the octave — slightly wrong.

The Compromise

Equal temperament divides the octave into 12 equal semitones, each exactly 100 cents apart. This means you can play in any key and every key sounds equally… acceptable. Not perfect. Acceptable.

A pure perfect fifth (the 3:2 frequency ratio found in nature) is 701.96 cents. In equal temperament, it’s 700 cents. Close, but not exact. A pure major third (5:4 ratio) is 386.31 cents. Equal temperament gives you 400 cents — nearly 14 cents sharp. That’s audible.

When It Breaks Down

For solo melody, equal temperament works fine. The problems emerge with harmony:

  • Open chords on acoustic guitar — the major third in an open E chord rings 14 cents sharp. With fresh strings and a good setup, this creates audible beating.
  • Barbershop and a cappella — singers naturally adjust toward pure intervals. A keyboard accompaniment in equal temperament clashes with what vocalists want to do.
  • Historical performance — music written before 1800 assumed temperaments like Meantone, Werkmeister III, or Young II. Playing Bach in equal temperament misses the intended color differences between keys.
  • Fretless instruments — violins, cellos, and fretless bass have no temperament constraint. Players intuitively use Just intervals.

Alternative Temperaments

Just Intonation tunes intervals to pure frequency ratios. The result is stunningly consonant chords — in one key. Move to a different key and things fall apart. It’s ideal for fixed-key pieces, drones, and modal music.

Pythagorean tuning stacks pure fifths (3:2). Melodically brilliant, harmonically rough. Medieval and early Renaissance music was written for this system.

Meantone temperaments narrow the fifths slightly to produce better major thirds. The standard for keyboard music from roughly 1500–1750.

Werkmeister III and Young II are “well temperaments” — they don’t make every key equal, but they make every key usable, each with its own character. This is what Bach’s Well-Tempered Clavier was likely written for.

How Lumituner Helps

Lumituner supports six temperament modes: Equal, Just, Pythagorean, Meantone, Werkmeister III, and Young II. Switch temperaments in the settings menu and the strobe target adjusts automatically.

This means you can:

  • Tune a guitar to Just Intonation for a recording in a single key
  • Set up a period instrument with Meantone temperament
  • Experiment with how different temperaments change the character of familiar chords
  • Verify that a fretless instrument is hitting pure intervals

The strobe display makes the difference between temperaments visible. Tune a major third in equal temperament, then switch to Just — you’ll see the disc shift as the target moves 14 cents flatter. That visual difference is the sound difference.

Start Exploring

Open Lumituner, tap the settings icon, and try switching between temperaments while playing a chord. Your ears — and your audience — will notice the difference.