I am a beginner in music theory and want to compose something in A Aeolian, but I just noticed that the same notes are used for C Ionian.

A Aeolian is supposed to be melancholic while C Ionian is likely a happy mood. Isn't that right?

  • Are you composing a choral in Gregorian modes or writing a song in classical or popstyle? Are you identifying C ionian with C major? And … alla Turca (Mozart) is in minor - is this a melancholic tune? May 13, 2022 at 14:00
  • As mentioned elsewhere, I'd suggest letting go of the "Aeolian = say, Ionian = happy" concept. The saddest song in the musical Hamilton is written in a major (Ionian) key.. May 13, 2022 at 15:05
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    I have bad news for you regarding D Dorian, E Phrygian, F Lydian, G Mixolydian, and B Locrian... :) May 14, 2022 at 1:31

7 Answers 7


There are two principle idea you need to learn about.

  • The tonic as the center of tonality in music.
  • The difference between keys in the major/minor system, key signatures, and modes.

The tonic is usually described as the "home" tone of a scale/key/tonality. If you are in the key of C major the tone C is the tonic.

The second idea is a bit more complex. But it's probably best to start with saying key, key signature, and modes are not synonymous ideas. The term keys is used for the major/minor system.

This isn't the place to go into a long description of "key", but briefly, keys have major or minor triad tonic chords with a dominant chord that uses a major third, that dominant's third being the leading tone of the key, which is also the scale degree one half step below the tonic scale degree.

Modes are similar to keys, but the treatment of harmony and scale degree is a little different in modal music compared to major/minor keys. Also, there are two main uses of the term modal. One being the system of music in the Middle Ages and Renaissance, and the other for more modern folk/jazz/pop styles. In both styles you can make a very broad generalization that modal harmony is not primarily about tonic/dominant chords. A tonic/dominant harmony focus is the hallmark of the major/minor system.

And finally, key signatures only define a collection of tones, but do not define a tonic. So, if given a key signature, like for example two sharps, we only know the collection of tones is C# D E F# G A B, but we don't know the tonic, so we don't know if the key signature means key D major, or key B minor, or mode A mixolydian, etc. etc.

Some people will say that your two modes C ionian and A aeolian are the same as keys C major and A minor. That is true only in the superficial sense that the key signatures of C major and C ionian and A minor and A aeolian are the same. But in terms of harmony, and the stylistic differences between major/minor keys and modal harmony, those pairs are not the same.

How to avoid C Ionian theme when I am playing in A aeolic?

You will avoid that by proper handling of the tonic for each mode. How to do that is beyond the scope of this question. You need a lot of study to get a good understanding. But a simple rule of thumb you can try is emphasize the tones of the tonic chord to establish the mode. So, for example in A aeolian, write a melody that emphasizes the tones A, C, E, especially at the beginning and ending of the music. Traditionally, the melody will start and end on tone A.

And A aeolic its supposed to be melancolic while C Ionian is likely an happy mood isn't that right?

Yes, that is the general idea. But don't take that idea too far. There are plenty of examples of music that do not fit that simplistic notion of mode and mood.

Technically we want to understand it's the third scale degree that is primarily responsible for the differing mood. In aeolian the third scale degree is a minor third above the tonic, while in ionian the third scale degree is a major third above the tonic. The differing major/minor quality of the third scale degree creates that difference in mood, or "color" as it is sometimes, and less subjectively, described.

You can consider other possible moods. Minor doesn't necessarily feel sad. It can be dramatic or confident. Major isn't necessarily happy. It can be stately or majestic. Many, many moods are possible. In addition to mode, rhythm and tempo are hugely important factors for creating moods.

  • I think the most useful part of this answer is "So, for example in A aeolian, write a melody that emphasizes the tones A, C, E, especially at the beginning and ending of the music.", except I would say "especially at the beginning or ending of melodic phrases". If you want to establish a minor mode before the very end of a piece, you can do it within a melodic period or sentence. I see it as analogous to language. Where one can say "I went to play football..." and that's neither happy nor sad until it's completed with "but it was rained out" or "and we won!" May 13, 2022 at 14:02
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    The OP said they were a beginner so I tried to avoid anything about form. I was thinking of a single line, something on the scale of Three Blind Mice. May 13, 2022 at 14:17
  • IMO, rhythm and form are essential tools in setting the mentioned emphasis to certain notes. But talking about how to use rhythm and form is more difficult than talking about which notes to emphasize... On this site, I guess we are constrained to talking about those aspects of music that can easily be talked about. :) May 14, 2022 at 22:58
  • Yes, rhythm and form are essential. But let's not get the cart in front of the horse. The answer needs to be a summary, with some caveats about key/mode, and then the OP needs to spend some time with fundamentals of music texts, some sight singing or solfege, and simple analysis before trying to compose. Then composition can be done at an appropriate level to extend what they've studied in texts and real scores. May 17, 2022 at 16:33

There are in fact many pieces which move in and out of C Ionian and A Aeolian. It's the way music sometimes works. And one of the reasons the key signatures are the same.

We tend to define the key of a piece using the note/chord that occurs at a place, usually the end of a phrase or line (the cadence) that feels like 'home' - a place where the piece has come to rest, and could end there. A piece said to be in C Ionian will have C as its resting note, and/or CEG as that chord.

A piece said to be in A Aeolian (A minor) will have that tendency towards A or ACE. Two of those chord notes are the same, which makes recognition that much more difficult.

To emphasise that 'home' chord, that cadence helps a lot. Particularly the perfect cadence - G>C, or e>a. G>C works particularly well, as there's a leading note (B). Sadly, (sic), there isn't such a mechanism in Am, while just using the Aeolian notes. There's no leading note, as G♮ is a tone below the tonic. That's why a lot of times, that cadence is E>a, using G♯ in the E chord.

You can still do that, which leaves you in key A minor, quite acceptable, as there actually isn't a key A Aeolian - only a mode - a set of notes taken from the parent C major.

So, in order to keep the feel away from C Ionian, avoid G>C, but use e>a, or E>a lots, especially at cadence points.

As far a 'melancholy' or 'happy' is concerned, they're maybe not the most apposite terms to use, as Albrecht points out.


Yes, the 2 modes contain the same tones. But the structure of the melodies in C compared with Am and the functions of the homechord are quite different.

Like Tim says it seems you ask how to differentiate C major from A minor (C Ionian and A Aeolian.

They have a different homechord and homenote. This means in C the first and final motif will fit to the CEG triad and A minor will contain the ACE triad. The final note will be A respectively A.

If theres an upbeat this might be G - C in the melody (= C) or E - A (= Am)

Mind that the leading tone in minor (even in A aeolian) may be altered to G#. The best indication is really the finalis (= final note, respectively last chord = hometone/home chord)

So you will have more intervals like the minor third G-E and the tone G will appear more often because it is the root note of the dominante while in Am the dominant (V) is E.

An interesting example is Obladi Oblada by the Beatles. The first 2 phrases could as well be in Am but the final phrase ,is leading to the root tone of C. Finally the Refrain makes sure this is C major.

I have overlooked the head of your question: (apologize!)

How to avoid C Ionian theme when I am playing in A aeolic?

You should avoid the line So-Fa-Mi-Re-Do and So-La-Ti-Do bcause this is the "key"-melody to tonicize the root tone of the ionian mode and the triad do mi so, while the melodic line mi so la and mi re do ti la is confirming the root note LA of the minor mode.


All the other answers give excellent information on solidifying the Aeolian mode, but there is one thing they don't mention.

Your biggest challenge will be to avoid accidentally slipping into C Ionian. So do everything the other answers suggest, use cadences on A, and emphasize the pitch A on strong beats of your melody. But here is the magic trick.

Whatever you do, don't emphasize the notes B and F.. If you use them at the same time in a chord they will point most certainly to C and you will use your Aeolian feel. If you inadvertently place these two notes too close together in your melody it will draw your ear back to C. If you use two consecutive chords with those notes, like F-A-C and E-G-B or G-B-D, boom. You will end up in C. You'll know you're in trouble when you try to cadence on A and it sounds unfinished.

Why?. These two chords form an interval of a diminished fifth, and it is an incredibly powerful interval that gives sort of a magnetic attraction to C. In fact, the diminished fifth is one of the reasons that using G# at a cadence helps. That notes creates a powerful pull to A because it is a diminished fifth away from D.


We already have good answers, and an accepted one, but it's a good question that's asked often in different ways, so I'll add one more perspective.

Many modes like C Ionian, A Aeolian, and D Dorian share the same set of pitches, but the difference is the center of harmony, the tonic. The center of harmony is not established by making an intellectual declaration such as saying to the audience "this is in F Lydian because I say so", the center is established in the listener's mind, upon hearing sounds. If the pitch set is C, D, E, F, G, A, B and the center of harmony feels like being C, then you say that the mode is C Ionian. But if A feels like the center of harmony, you say the mode is A Aeolian. Your own feelings decide what the mode is to you.

Believe it or not, but two people can listen to the exact same music and perceive a different harmonic center.

Your question is like asking, "how can I move around and keep my center of balance in the same place and not fall over?" If a person does not have the capability to stay upright in balance without falling over, you cannot really explain it to them in intellectual means and have them "understand" how to stay in balance so that they can actually do it. It's a complicated skill of coordination, and even though it can be explained and reasoned about by using physical terminology, you cannot learn to do it by sitting on physics classes. You learn it by doing. Teachers can give you hints and coaching, but you have to learn it yourself.

It's the same with harmonic balance.

In my opinion, the most important factor in placing the center of balance on a particular pitch is rhythm, including pulse and overall form. Another factor is, what the bass note is.

Use a pedal point

One quick and dirty fix for placing the tonic is to play a low pedal point. Play a constant low A bass note or bass rhythm pattern, and it will almost certainly lock the mode to A Aeolian, if all the other notes are from the appropriate scale. Play a constant low C bass, and it will lock your ear to C Ionian. You can compare this to a ship's anchor, it restricts motion.

But a pedal point is a brutal tool for placing the tonic - a good player should be able to place a tonic even by melodic notes alone, without a bass. However, I've noticed that the bass note can help as a guide for melodic experimentation, for developing a sensibility for moving the tonal center. Use a pedal point as a learning aid.

Rhythm affects perception of tonal center

Rhythmic form is an essential tool. What kind of rhythmic pulse do you sense in your mind? Is there a meter where pulses are grouped to measures, or some larger form? Where do notes land relative to the pulse, meter and form? This affects which notes are perceived as having emphasis. And actually, everything affects everything interdependently - whatever notes or other sounds are heard, affects the sense of pulse, meter, and form. And if a sense of pulse, meter and form has been established, all other notes are sensed relative to that.


Two people arrive at different times to a place where this constantly repeating sequence is playing:

note sequence without barlines

How do they perceive the harmonic center? Is it C, D, E, F, G, A or B? Try it: can you make it sound like it's in D Dorian? Play a 4/4 drum beat that starts from the D-F-A chord - does it sound like D Dorian now? How about if you start the beat from the C-E-G chord, does it sound like C Ionian then?

  • +1 for the comparing melodical/harmonical with physical balance and the hint pedalpoint May 18, 2022 at 4:38
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    @AlbrechtHügli Yes, I think harmonic balance is very much comparable to physical body balance. That's how it intuitively feels to me, and how it should be taught and learned IMO. You learn to feel where the balance is, walk and jump around and gradually you learn to sense and control your balance, like a child learns how to walk or ride a bicycle. Like they say, walking is controlled falling. It's not possible to learn physical or musical balance control by reading books and reasoning. I added a remark of a pedal point being like a ship's anchor, that's a good analogy too. May 18, 2022 at 10:57

I'm not sure about modern modal uses but the problem of having a minor key composition drift into the relative major has been known for some time (maybe 500 years or so). There are some techniques for alleviating the problem. The biggest ambiguity between a minor key and its relative major is having a VII-III chord sequence in a minor key. Example: in A minor, playing a G major chord followed by a C major chord is aurally equivalent to an authentic cadence in the key of C major. The reverse iii-vi (E minor to A minor) doesn't sound so much like the key of A minor as the chord on E is usually major; it's a bit more complicated the chords sequence v-i is often used throughout a minor key but the same piece may use V-i (E major to A minor) at important parts (cadences at the end of sections.)

Another way to emphasize the minor key is to make sure that VII-III occurs in some sort of sequence (like a cycle of fifths.) (Using lower case for minor and upper case for major chords, 7 for dominant sevenths, and 0 for diminished chords), a section like a-d-G-C-F-b0-e-a will tend to sound like it's in A minor as the sequential nature of the pattern dominates the sound. Even more powerfully indicating A minor would be to replace the e-a chord pattern with E-a or E7-a the last time the pattern appears.

Other methods include using the "raised" version of scale steps 6 and 7 in ascending melodic passages and the "lower" form in descending. That is E-F#-G#-A going up and A-G-F-E going down. (Or E-F-G#-A going up.) I've written more extensively about this here (and on Quora). You can search for questions on minor-key harmony and the like.

The problem of the major key slipping into its relative minor doesn't occur as often (probably because of the lack of an "accidental" authentic cadence in the relative minor.)


If you're composing or improvising music in A minor, one way to break the relationship to the relative major is to slip out of that natural minor mode into the melodic and harmonic minor. Consider that in the A melodic minor, the run of notes starting on C (C, D, E, F#, G#) form a whole note scale. The ear might perceive a do-re-mi for the first three three, but after that it bears no relation. The cadences involving the G# leading tone resolving to A will firmly tend to anchor the music to the minor mood.

Which mood is perceived by the listener is a complicated result from numerous factors. For instance, try this: (all 16th notes with ---- indicating a quarter):

C-D-E-F E-D-C-B A-G-A-B A----

G-A-B-C D-C-B-A G-A-B-G A----

To me it sounds grounded in the mood of the A minor scale, in spite of the phrases beginning with do-re-mi-fa tetrachords rooted on C and G; that is, exactly some of what you say you're trying to avoid). This is probably a combination of

  1. Past exposure to hearing these kinds of phrases together with a harmonic interpretation in more complex pieces of music featuring chords and counterpoint.

  2. Emphasis on the ending note A, which leaves a stronger impression than the starting notes, probably because it is longer and more recent. Also, the previous beat before the longer A contains only two different notes A and G, and A is repeated. It is already signaling a convergence on the A.

  3. In the first phrase, the emphasized notes (first notes of each quadruplet) are C, E and A, belonging to the Am triad.

  4. The second phrase after the first fits a known pattern: the music shifts to the G, which the deceptive dominant in the G-Am cadence. So that is to say, Am music sometimes goes to a higher energy point centered on G (rather than, say, E), which falls back to A. We perceive the second melodic line as the "G response" to the "A call", and therefore that it fits together and continues in that mood.

If you have an accurate intuition for this sort of thing that think you can trust, then all you have to do is generate melodies and judge whether they have the effect you want. If not, replace them by something else until it works. If the music is going to be harmonized, it's not necessary for the melody alone to set the mood. Melodies that are "ambiguous" in some sense can acquire their "direction" from other notes.

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