Equal Temperament vs Just Intonation: Tuning Scales and…

What is Equal Temperament?

Equal temperament is a system of tuning where the octave is divided into twelve equally spaced semitones. Each semitone is tuned so that the frequency ratio between successive notes is exactly 2^(1/12). This ensures that all twelve notes are in perfect harmony with each other, making it possible to play music in any key without significant tonal imperfections.

The equal temperament system was developed to address the limitations of just intonation, where certain intervals produce more consonant and pleasing sounds.

What is Just Intonation?

Just intonation uses pure frequency ratios between notes, such as 3/2 for a perfect fifth and 5/4 for a major third. These intervals are considered to be the most consonant and pleasing to the human ear.

However, using just intonation requires different tunings for each key, which can lead to tonal inconsistencies when moving from one key to another.

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The Disadvantages of Equal Temperament

While equal temperament provides a consistent tuning across all keys, it does not produce the same level of consonance as just intonation. This is because the intervals in equal temperament are slightly out of tune compared to their pure counterparts.

The result is that some intervals, particularly thirds and fifths, sound less pure or 'beating' when played on instruments tuned using equal temperament.

Why Does It Matter?

The choice between equal temperament and just intonation has significant implications for the sound quality of music. Composers and musicians must decide whether to prioritize consistency across keys or the purity of individual intervals.

Historically, some composers have written pieces specifically for just intonation to take advantage of its more consonant intervals, while others prefer the versatility provided by equal temperament.

Frequently asked questions

What are the main differences between equal temperament and just intonation?

Equal temperament divides the octave into twelve equally spaced semitones for consistent tuning across all keys, whereas just intonation uses pure frequency ratios that vary depending on the key, providing more consonant intervals but less consistency.

Why did equal temperament become the standard in Western music?

Equal temperament was adopted because it allows musicians to play in any key without significant tonal imperfections and provides a consistent tuning across all instruments, making it ideal for ensemble performances and compositions requiring modulations between keys.

Can equal temperament be used with just intonation?

Equal temperament can coexist with just intonation in certain contexts. For example, some pianos are tuned using a combination of both systems to balance consistency and consonance.

Are there any modern instruments that use just intonation exclusively?

Some traditional instruments like the sitar or certain stringed instruments used in Indian classical music often employ just intonation for their specific tuning requirements, but these are not common in Western music due to the challenges of maintaining consistent tuning across keys.

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Equal Temperament vs Just Intonation: Tuning Scales and Their Implications