Classical Music 101: What does it mean to be in tune?

It sounds pretty simple when someone says that a singer, an orchestra or a piano is in or out of tune.

But the search for the right tone lowers the drawbridge on a world of physics and fashion that has, for centuries, been the preserve of the most diehard musical geeks inhabiting a hothouse of jealousies, intrigues and infighting.

I’m prompted to write about this today because the Physics Blog at the MIT Technology Review is trumpeting the latest computer advance designed to make the human piano tuner obsolete.

If only the world of tuning were that simple.

First, everyone needs to agree on a common note to use as a reference point.


Tonight, when concertmaster Jonathan Crow stands up in front of the Toronto Symphony Orchestra at Roy Thomson Hall, he will ask principal oboe Sarah Jeffrey to play an A on which the whole orchestra will tune.

Simple enough — except that, at nearly same moment, Charlotte Nediger will play a different A for the Tafelmusik Baroque Orchestra at Trinity-St. Paul’s.

That’s because the actual pitch of that A has varied over the centuries. Official modern concert pitch is an A that produces sound waves measuring 440 Hz. But many musicians are tempted to cheat, because a fractionally higher pitch makes for a brighter sound (some orchestras, like the New York Philharmonic, tune at 442 or 443 Hz).

Baroque pitch is lower — and all over the map. Scientists couldn’t measure the amplitude and duration of sound waves until 150 or so years ago, so people relied on the craftsmen who made tuning forks and pitch pipes. At the extreme, these tuning standard could be two or even three full tones apart.

Each period-performance ensemble sits down — sometimes before each new concert programme — to decide what frequency they will use as their tuning standard (for example, if they are building a concert around a historical organ, which is difficult to tune, they will tune themselves to that instrument).

The official modern concert pitch standard of A=440 Hz was only confirmed in 1939, by the ISO.


If you listen to the organ at University of Toronto’s Knox College, then walk down the drive to listen to the same piece of music on the organ at Convocation Hall, it will sound different. That’s not only because the instruments are tuned to a different pitch, but also to a different temperament, which sets up the intervals, or gaps, between notes from one end of the keyboard to the other.

The Laws of Physics, inconveniently, don’t allow for equal increases in frequency when going up the Western halftone scale. If anyone were to try that, the instrument would, ironically, end up sounding completely out of tune. This means that all instruments have to cheat some intervals as they go up and down the scale.

The codified, modern system of cheating is called equal temperament — made famous by J.S. Bach in his two books of Preludes and Fugues for all 12 possible major keys and their minor-key relatives.

Until the 18th century, keyboards were tuned using a number of alternate tuning systems that focused on solving problems with thirds or fifths, usually in particular keys. (Still today, wind-instrument players find it very difficult to play in certain keys, for tuning reasons, so sympathetic composers try to avoid writing in those keys.)

The Knox College organ is tuned using a mean-tone temperament, which goes back to Pythagoras, the Greek geek who, besides figuring out musical intervals, gave us the key to measuring the length of the sides of right triangle.


What we hear as in-tune, is really a combination of traditions and habits that our ears interpret as being correct.

Leonardo da Vinci, should his time machine send him to Roy Thomson Hall tonight, would find the sound strange, if not alien.

Think this is all about splitting hairs? Here are Frédéric Chopin’s 24 Préludes played by Michele d’Ambrosio on a piano tuned in an unspecified variation of unequal temperament:

John Terauds


3 thoughts on “Classical Music 101: What does it mean to be in tune?

  1. John —

    In the classical music literature there is often discussion about the “quality” of certain keys. I.e. “the joyous key of C major”, “the sublime key of Ab major” etc. when used to describe the work of classical composers (and their choice of key). I’ve often wondered how one could ascribe these qualities to particular keys, all of which should theoretically sound the same in modern tuning.

    Some ideas:

    1. These are associations based on other known works (e.g. “I wrote this work in C minor because Beethoven’s 5th is in that key, and I wanted to evoke the same mood”)

    2. The associations are based on people who have perfect pitch and thus an internal set of absolute pitch references (seems unlikely)

    3. The associations are based on the tonality of particular instruments playing within their ranges (also seems unlikely, especially in orchestral music)

    4. The associations come from the legacy of earlier temperament systems and the qualities of chord tones (flat vs. sharp) in particular keys.

    Number 4 seems most likely to me. What say you?

    • Yes, Jordan, No. 4 is the likely cause.
      In fact, the literature associated with different deperaments specifically mentions certain keys that contribute to brighter or more sombre tonal qualities.
      People who really know about these things complain about how modern equal temperament has homogenized the qualities of different keys.

  2. As an addendum, and as a woodwind player, I wouldn’t say that wind instruments are necessarily easier to play in tune in particular “keys”, but rather that certain notes are notoriously difficult to tune. For example, on all saxophones, the written D just above middle C (which sounds as F below middle C on an alto saxophone) is always flat, and difficult to bring up. So a composer might consider avoiding exposed sections with that particular note (didn’t stop Glasunov in his saxophone concerto, who has a few tied whole notes down there).

    Another reason for a composer to avoid certain keys is simply mechanistic. Woodwinds are “designed” around playing in written C major. Keys like Db and F# tend to involve a lot of “pinky work” and forked fingerings. Clarinet players solve this by simply switching from Bb to A clarinets, to change the “effective” key and simplify tricky passages. Other woodwind players don’t have this luxury.

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