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Equal Temperament vs Just Intonation: A Beginner’s Guide

Guitar head

Have you ever wondered why your guitar sounds a certain way, or why some chords seem to ring out more clearly than others? It all boils down to musical tuning, the system that determines the specific pitches of your strings.

In this article, I’ll be diving into the world of tuning systems, specifically comparing two main approaches: equal temperament (ET) and just intonation (JI). Even if you’re not a music theory whiz, don’t worry! We’ll break it down in a way that makes sense for every guitarist (and other musicians).

Equal Temperament (ET) – A Western Music Solution

The most common system, and the one you’re probably familiar with, is called equal temperament (ET).

Here’s the basic idea:

Think of the space between two notes on your guitar, like the gap between E and F. In ET, we take that octave (the full range from E to the next E) and slice it up into twelve equal steps. Each fret you move up the neck represents one of these steps. This even spacing makes ET super versatile.

In other words, if you’re playing guitar, ET is the only type of tuning you’re using.

Here’s why ET rocks for guitarists:

  • Plays nice in any key: Because the frets are all spaced the same, you can comfortably play chords and scales in any key without retuning. This is a huge advantage compared to other systems.
  • Simple and familiar: ET is the standard tuning for most fixed-fret instruments. You already know how to use it! No complex calculations or adjustments needed.
  • Practical for guitars: The fixed frets on a guitar make ET a perfect fit. You can focus on playing music without worrying about constantly fine-tuning each string.

Now, there’s a slight catch. This equal spacing in ET means some intervals (like fifths) might sound a touch less smooth compared to another tuning system called just intonation (JI). But that trade-off is worth it for the flexibility and ease of use that ET offers.

It’s worth mentioning that while 12-tone ET is the most widely used, there are other flavors of ET out there. These less common temperaments might divide the octave into a different number of steps, like 19 or 31. These alternative ETs aim to achieve a different balance between consonance and versatility. However, due to the practical limitations of fixed-fret instruments like guitars, 12-tone ET remains the most practical choice for most guitarists.

The 72 ET scale is probably the most interesting one out there. It was used in Byzantine chants, according to Wikipedia. It’s like there are six different microtones between each of the 12 steps. Here’s how that sounds, in case you’re wondering. I know – weird!

Just Intonation (JI): Tuning for Purity

We’ve explored the world of equal temperament (ET), the workhorse tuning system for most guitars. Now, let’s delve into a different approach: just intonation (JI).

Here’s the key difference between JI and ET: JI uses basic math relationships between notes, like simple fractions (3/2, 5/4), to create intervals. Imagine plucking a string – it vibrates not just at its main pitch, but also at higher frequencies that are multiples of the main pitch. These faint higher tones are called harmonics. Certain harmonics create especially smooth and pleasing sounds when played together. JI tuning aligns the pitches of different strings based on these harmonic sweet spots, resulting in pure and resonant intervals.

So, why might a guitarist consider JI?

  • Heavenly harmonies: Chords played in JI can sound unbelievably rich and pure, with a depth and complexity you might not experience in ET.
  • Emotional connection: JI allows you to tailor the tuning to a specific key, potentially enhancing the emotional impact of your music in that key.

But JI isn’t all sunshine and rainbows. Here’s the flip side:

  • Key commitment: Unlike ET where you can play in any key, JI requires retuning the guitar for each key you want to play in. This can be a real hassle for guitarists who like to switch things up.
  • Fret no more (literally): The beauty of JI clashes with the reality of fixed frets on a guitar. Since JI uses slightly different intervals depending on the key, it’s impossible to achieve perfect JI on all frets with standard tuning.
  • Theory time: Understanding JI requires a bit more music theory knowledge compared to ET.

Conclusion: Equal Temperament vs Just Intonation?

This whistle-stop tour through tuning systems hopefully sheds some light on the battle between equal temperament (ET) and just intonation (JI) for guitarists. Remember, ET offers unbeatable versatility and ease of use, making it the go-to choice for most guitarists who need to play in various keys. JI, on the other hand, unlocks a world of pure, rich harmonies that can elevate your music in a specific key.

While there are other tuning systems out there, like alternative temperaments with more than 12 tones or microtonal tunings, achieving them on a standard guitar with fixed frets becomes quite a challenge. Additionally, JI’s key-specific nature means frequent retuning, which isn’t exactly ideal for most guitarists.

So, what’s the takeaway? Experiment! Play around with ET, the familiar friend. Then, if you’re feeling adventurous, delve into JI and explore its sonic potential. The world of tuning is a fascinating playground waiting to be explored. By understanding the options and their pros and cons, you can choose the tuning system that best suits your musical goals and unlocks your unique voice as a guitarist.

Some popular tuners can help you tune based on JI, including Peterson, which features the popular sweetened tunings.