What is absolute pitch?

posted on November 16, 12018

There are widespread misunderstandings about what exactly it means to have “absolute” (or “perfect”) pitch, even among trained musicians and music students.

Some believe that absolute pitch is about the ability to tell whether a performer or instrument is “in tune” or “out of tune”. One popular misconception is that those with perfect pitch are irritated by music that is played in a different key, or in any “key” outside of the most common A440 tuning.

Maybe the most common belief about absolute pitch is that it is a skill that a person must be born with and can never acquire through practice.

These are misunderstandings of what absolute pitch means. I am of the opinion that nearly everyone (who is not tone-deaf) has some level of “absolute” pitch. I am further of the opinion that virtually everyone can improve their ability to discern pitches.

An analogy

Some of us are colour-blind, but most of us have learned the ability to distinguish “red” from “blue” and both of those from “green”. We rarely think about this, but how do we do this? What process goes on in our minds when this happens?

When light hits our eye at a particular wavelength, we remember that wavelength, approximately. If asked to pick out the colour of your toothbrush1 on a colour wheel, you could almost definitely do so, more or less. Some of these colours have been given names by us, such as “green” or “yellow” or “violet” or even “vermilion”.

In fact, because wavelengths are continuous, the names we have ascribed to these colours do not identify just one particular wavelength but in fact a whole2 range of wavelengths.

People who can easily (even automatically or subconsciously) distinguish “teal” from “cyan” might be said to have “absolute colour”. This is the equivalent of music’s absolute pitch.

The test

To demonstrate my point, I prescribe a simple test.

A typical piano has 7 complete octaves (ignoring a few “extra” keys at the bottom or top). Assign each octave a label from 1 to 7. Next, have a friend (or a computer) play notes on the keyboard at random and try to discern the octave of those notes.

Most people who have seriously studied piano can do this accurately. This is absolute pitch.

People who are said to have “absolute” pitch are passing this exact test, except about 12 times more accurately. They can discern individual pitches rather than octaves, but the skill necessary is exactly the same. At the physical level, they can remember what a particular wavelength “sounds” like.

Distinguishing the middle octave from the next higher one is like telling green from yellow. Distinguishing an F from a G without context is akin to knowing (essentially, remembering) the difference between indigo and ultramarine.

This works in the opposite direction as well. If somebody showed you something indigo and something ultramarine and asked you to identify which was which, maybe you could do so because you know that “ultramarine is closer to purple”3 or some such thing.

Being able to put a label to a frequency without context is the crux of both absolute pitch and absolute colour.

The spectrum of wavelengths is continuous

It’s worth pointing out here that, just as wavelengths of visible light are not discrete, neither are musical pitches4. It’s not as if there is an A wavelength and a B-flat wavelength with nothing in between. As you observe shorter wavelengths, the pitch of the note exhibits a gradual rise (from A to B-flat, in this case). This is why musicians, especially string and wind players, often talk about intonation and notes being slightly too “sharp” or “flat”. Many musicians can do this whether they consider themselves to have absolute pitch or not, because even without knowing the particular note, the context of other notes around it is sufficient to tell whether a note is “out of tune”.

In a sense, what is considered “absolute” pitch and what isn’t is somewhat arbitrary. You are said to have this skill if you can tell apart the 12 tones of the Western scale. But why must there be 12?5 In a culture where the octave is split into 5 notes instead, we would expect many more people to be deemed to have “absolute” pitch; in a world where the octave contains 42 notes, very few would.

Many have commented to me that they would never want to experience absolute pitch, as they feel it would be too great of an annoyance to hear notes that are “out of tune”. I hope that by now you understand that this is not an accurate picture of what absolute pitch is.

Notes can only be out of tune with respect to something else, which is most often the other notes, but can also be the system of labels we’ve invented. You might hear, for example (particular with older orchestras), instruments that are tuned such that their A is tuned to 415 Hertz6 instead of the more common 440. However, as long as all the notes are in tune relative to each other, there’s no reason anybody should be upset by this, at all. All that’s changed is the labels we’ve given them. The range of frequencies in the Baroque orchestra that was called A was slightly lower than what we now call A, and it isn’t the physics that has changed; it’s our language.

Imagine that a friend told you that their car was blue, but upon seeing it, it happens to be closer to what you would call blue-green.7 That’s the kind of disagreement we’re talking about here.

Similar logic applies in the case of works played in keys other than their original. I’ve never met a person with absolute pitch who would prefer to hear a performance of a Schubert song in their original key than in a different key that was better-suited to the performer. If they know the song, then they will know that it’s in a different key, and that’s completely fine. Absolutely nobody is judging you for singing in a key that better fits your range — in fact, they might judge you more harshly if you didn’t.

I would like to point out that I’ve never known anybody with strong absolute pitch to say they find these things troublesome. As far as I know, these are only things that other people suggest are common occurrences. It should perhaps come as no surprise that those with strong absolute pitch tend to have a better intuitive understanding of what it means than those who don’t.

“Relative” pitch

In light of all of the above, I find this controversial8 term meaningless and I discourage its use.

When people say that they have “relative pitch”, what they nearly always mean is that they have learned to identify notes based on a point of reference (often the tonic of the current key). Having been told that some previous note is a G, they can correctly name every note by listening to the intervals above and below that G.

What they might not realize is that what they are really doing here is the exact same thing that those with absolute pitch do all the time. They have a note in their head which has a label associated with with and to which they are comparing other notes. There is no part of this which differs from absolute pitch, except that the listener doesn’t expect to remember the note after some amount of time has passed.

Absolute pitch is relative pitch, except that the reference note comes from long-term memory.

Piano tuning

The piano is a special case. It’s not unusual for a person to play a single note on the piano and for a listener to hear that the instrument is out of tune.

How can this be? Without seeing which key was depressed or hearing how the others are tuned, who is to say whether the rest of the notes aren’t all in tune relative to each other?

On the piano, a single key can be out of tune with itself because most keys play 3 strings. If those strings are not of the same length and tension, the single key will generate multiple frequencies simultaneously, and thus be out of tune.

The large majority of instruments do not have this problem, and it is not possible for a note to be out of tune with respect only to itself.9

Terminology

As nearly everyone can tell a “high” note on a piano from a “low” one, with or without context, I like to say that almost everybody has a level of absolute pitch and that it can be improved with practice and exposure.

But that doesn’t mean there isn’t practical value in having a label that describes the ability to identify individual notes in the most common (12-tone) scale with no context. For that reason, I’ve taken to referring to this as 12-tone absolute pitch or the maybe more convenient strong absolute pitch. Those who can tell high from low without fine precision can be said to have weak absolute pitch.

It is my hope that by reframing the matter in these terms will clarify that absolute pitch is not a unique talent, available to few but inaccessible to most. It is rather a skill that (not quite) all humans have innately and can strengthen with experience. There is very little in life that is more universally understood and appreciated than music. It is not something reserved for gifted elites.


  1. Or alternative common everyday object of your choice.

  2. I considered saying a “large range” of wavelengths here, but then I reconsidered and thought maybe “small range” of wavelengths was more appropriate. In fact, as wavelengths range from zero to infinity, the concepts of “small” and “large” are meaningless without context. It is equivalent to asking the question: is 100 a large number or a small one? That said, the spectrum of visible light is not infinite. Although it varies slightly by person, according to Wikipedia, light is generally considered visible if it has a wavelength between 400 and 700 nanometres. How many labels you want to cram into this range is entirely your prerogative.

  3. I have no idea whether it is. Note that I would not have said “ultramarine is darker” because the white-black spectrum is on a separate axis from the red-violet spectrum, and besides, I have no idea whether it is.

  4. In fact the terms “pitch”, “frequency”, and “wavelength” are essentially synonymous when discussing music.

  5. There are in fact good mathematical reasons to divide the octave into 12 tones, but that’s for another time.

  6. This is the first time I’ve used this term here. I feel it needs minimal introduction as it literally means “one per second”. It’s named after some nerd whose name I forget.

  7. Maybe somebody three hundred years ago would have called it blue.

  8. The Wikipedia page for relative pitch cites only one source, which doesn’t once mention the term.

  9. An even specialler case is the organ, a somewhat customizeable instrument in that it has switches (called “stops”) which activate or deactivate various sets of pipes, into which air is blown when keys are depressed. It’s very possible for a key to be in tune when one stop is disabled but out of tune when it is enabled. Further, some organs have stops that produce different frequencies on purpose, such that some set of pipes plays a 4th or 5th higher or lower, or indeed in different registers.