Compose Yourself: Transposition, Friend Or Foe?

While “Measure for Measure” continues its pursuit of “power tones” (non-chord tones that yield some of the most expressive, beautiful moments in melody), we will pause a moment to delve into transposition, a technical topic of high value to performers and songwriters alike, and oftentimes a thorn in the side for guitarists.

To transpose means to change keys, that is, to uniformly ratchet the melody or harmony up or down a few notches to a new range of notes. Transposition comes in handy when you want to accommodate singers, instrumentalists, or orchestras that may have a variety of reasons to prefer one key over another.

If you happen to have perfect pitch, then changing keys will alter the character of a composition. In other words, if Mozart composed a symphony in G minor, he would have felt everything had changed if it had been transposed to A minor. However, for most of us, transposition is something like driving a pickup truck up or down a mountain. The altitude may change, but the appearance of the truck does not—we’d recognize it anywhere. Same with a transposed melody: The notes are different, but the tune is the same. This is because the intervals are all the same, and most of what we experience in music has to do with intervals, key (major or minor), and scale tone mood. Absolute pitch doesn’t enter into it.

By the way, it makes no sense to talk about “transposing major to minor” or vice versa. A change from major to minor is called a “change of mode,” which is a whole different kettle of fish. In the type of transposition we’re talking about, major keys stay major, minor keys stay minor. This is called chromatic transposition, which means that all tone relationships stay the same in the new key. “Chromatic” means that it makes use of the chromatic scale (all the tones available on the keyboard or guitar). There is a second type of transposition called diatonic, which uses only scale tones in the original key. We’ll come to that in a moment.

Anyone who has tried transposition knows it can be tricky. This is why some folks think of it as a “foe.” Others, myself included, think of it as a friend, however. Learning how to transpose makes you a more versatile musician, causes your ears to grow very large (you start to hear musical ideas more clearly), and—take heed, jazz, rock, blues improvisers—greatly enhances your ability to quickly find notes on your instrument.

Guitarists are in a unique position when it comes to transposition. Some things about the guitar make it easy. Other things make it difficult. We will deal with both sides of the issue next time. Right now, let’s see how transposition works.

Suppose we transpose a melody first.

Our imaginary hit tune starts out “Do – Re – Mi,” which means we sing the notes “C – D – E” in the key of C major. The lead singer in our group, however, being a bit of a diva, insists on singing in the key of D major. So what do we do? We transpose “Do-Re-Mi” from the key of C to the key of D; that is, we move the melody up a step, so that it starts on “D” instead of “C”.

Every major scale has seven tones—Do – Re – Mi – Fa – Sol – La – Ti—regardless of the key. Since “Do – Re – Mi” means scale tones “1 – 2 – 3,” we play scale tones 1 – 2 – 3 in the key of D major—D – E – F#—and voilà, we have transposed our hit tune to the key of D. Note that “F” (a white key in the key of C) must change to F# (the black key to the right of “F”) when we change to the key of D in order to preserve the “Do – Re – Mi” sound. I call this technique “transposing by the numbers,” and we’ll come back to it in a moment.

Now let’s transpose harmony.

As fans of Ferris Bueller’s Day Off, we have an urge to sing “Twist And Shout” every now and then. Playing “Twist And Shout” in the key of C uses the chords C – F – G (C major – F major – G major). But as you know, our singer prefers the key of D. No problem—we just transpose the chord progression from the key of C to the key of D. In other words, we slide everything up a step: C major becomes D major, F major becomes G major, and G major becomes A major. The new chord progression, which sounds exactly like the old chord progression, just a tad higher, is D – G – A.

This “counting fingers” method of transposition works nicely if we’re not moving too far, but what if we’re transposing into outer space—from C to Ab, for example?

The easiest way to do this is, again, by the numbers:

The seven tones of C major are C – D – E – F – G – A – B.

The corresponding tones of Ab major are Ab – Bb – C – Db – Eb – F – G. This set of tones will sound a lot like C major, but the home-base tone (the tonic, scale tone 1) will be Ab, rather than C.

Now transposing becomes easy: We simply number the scale tones of the original melody, then use the equivalent scale tones in the new key, as identified by the numbers.

By the way, how do we know that Ab major has four flats? Memorization, alas. It’s the only way unless you want to go running to Google every time the occasion arises. It’s called “musical literacy,” and it’s worth cultivating. There are a couple of shortcuts to memorizing the key signatures, however, and I will cover those in another blog. For now, just trust me: Ab has four flats: Ab, Bb, Db, and Eb.

Transposing the melody from C to Ab: Since our melody uses scale tones 1 – 2 – 3 (Arabic numerals stand for scale tones), we simply find 1 – 2 – 3 in the key of Ab. That would be Ab – Bb – C, and presto, we’ve transposed the melody to the key of Ab.

To transpose the entire melody, we just continue to go by the numbers. This only gets tricky if one of the melody notes is altered, that is, shifted up or down a half step or two. Suppose, for example, that the original melody (key of C) went all bluesy on us and used an Eb every now and then instead of E natural.

This alteration means we have to alter scale tone 3 in the Ab melody: we have to flat it, or move it down a half step (one fret). Scale tone 3 in Ab is “C”, so we play “Cb” whenever we come to an Eb in the original melody.

“C FLAT? Isn’t that a little weird? I mean, ‘Cb’ is the same as ‘B’, isn’t it? Why don’t we write a ‘B,’ then? Come on—keep it simple, dude.”

I hear you, but we don’t take the easy way out because we’re talking about a flatted scale degree. That’s critical information to a musician reading our score. They have to know that it’s a flat 3, which means we must write “Cb.” To write “Ab – Bb – B” would imply that the scale had two B’s in it. It’s like spelling “cat” with a “k.” Yes, it sounds the same as “cat,” but it’s neither cute nor clever. It just shows we don’t know how to spell, and literate musicians will feel annoyed and mistrustful after that.

How about the chord progression? The process is the same, but we use Roman numerals rather than Arabic numerals to represent chord roots. The C – F – G progression is I – IV – V in the key of C. In other words, the chords are based on the first, fourth, and fifth degrees of the scale. In the key of Ab, the chord roots I, IV, and V are Ab, Db, and Eb. Let me illustrate:

Key of C:

I – II – III – IV – V     =     C – D – E – F – G

Therefore, in the key of C:

I – IV – V    =    C – F – G

Key of Ab:

I – II – III – IV – V    =    Ab – Bb – C – Db – Eb

Therefore, in the key of Ab:

I – IV – V    =    Ab – Db – Eb

As soon as you figure out what chords you need, you can start strumming away. Another option is to skip all this figuring and use a capo (a clip that fastens to the neck of the guitar and automatically moves all your chords into a new key). I will talk about capos in my next blog, because they are more than just a shortcut—they are a great help in understanding music theory, especially as it applies to the guitar.

Chromatic transposition, then, means moving everything up or down an equal distance, that is, an equal number of half steps. As a practical matter, this means an equal number of adjacent keys on the piano or frets on the guitar.

Diatonic transposition means shifting a group of notes up or down within the scale—no non-scale notes. It applies primarily to melody and only rarely to harmony. While chromatic transposition usually shifts a whole song to a new key, diatonic transposition almost always shifts part of the melody to a new set of scale notes. The cool thing about diatonic transposition is that it changes the character of the melody. In other words, your pickup truck miraculously gets a new paint job when you drive it up the mountain.

In The Beatles’ “All You Need Is Love” we hear a diatonic transposition of the “Love, love, love” theme (“Mi – Re – Do”) when it rises a step up to “Fa – Mi – Re.” This results in a dramatic change of character for these three notes. Incidentally, it also results in a “melodic rhyme,” a topic covered in other “Measure for Measure” columns and an e-book. All diatonic transpositions form a melodic rhyme of some kind.

The next blog will show how to transpose chromatically and diatonically on the guitar. If you want to break into the advanced levels of guitar playing, this is something you absolutely must know.