A good source to learn the theory of chords in an accordion

Question

I have been learning to play accordion for a few months and I can play 15-20 songs with their chords now. I know the physics behind the musical notes (such as I can understand what one implies by saying A has 55, 110, 220 Hz., etc.) since I know signal processing but I don't know how the chords are created: major, minor, 7, and dim. That is, I know the physics part, but I lack musical background. I suppose that I have the fundamentals to learn them by reading but I don't know where to look since I've no experience with musical terms. Would you recommend me a good tutorial or a book on harmony (especially using accordion)?

In addition, I would be appreciated if there is any source discussing on how to create chords for a song? I bring a song to my teacher, he checks the notes and writes down the accompanying chords. There should be a reasonable way to do this myself I guess.

Answer 1

Most teachers regardless of whether they teach piano, guitar, voice, or tuba, should be teaching you the basics of music theory. This should include key signatures, time signatures, note durations, and how chords are made, inverted and arpeggiated. Since you mention major, minor, diminished I assume you are learning western music vs other world music. Because by in large many accordions have buttons that play chords perhaps your teacher is not so concerned about chord construction?

Traditionally in western music chords are built on scales. There are many types of chords but the most basic chord is the diad, or double stop, two notes that are sounded together. Typically, diads are major or minor 3rds or 6ths, or 10ths, and often compliment each other.

However diads can be ambiguous as far as defining tonality. Since they are composed of only two notes it can be difficult at times to determine the exact scale one is playing unless there are enough of these to define a scale.

On the other hand, triads are three note chords that generally leave no doubt about their tonality and scale being performed. A major triad is played with the root, maj. 3rd, and perfect 5th.

In a major scale you will have the following chords from tonic to tonic: major chord (tonic), minor chord (supertonic), minor chord (mediant), major chord (subdominant), major chord (dominant), minor chord (submediant) and diminished (leading tone). All of these chords have a scale degree as the root note, then a 3rd and then a 5th (not always perfect).

More here but referenced to guitar: http://www.zentao.com/guitar/theory/chord-scale.html

Chords can have more than 3 notes, there are dominant 7ths and 9th chords and even 11ths thrown in as you build your repertoire to include music from the classics to jazz. Also chords do not have to have all the members played, you can easily have a root, a 5th, a 9th in one chord.

Chords can be implied by arpeggios so the notes do not all have to sound together, but can imply the same by being played as a string of notes.

Also you will learn that in the 20th century many western music composers abandon tonality for atonality.

In these works you will find no sense of a key center, and you may find the use of tone clusters which are chords made of several notes in an unusual order. Or mega chords that might expand the entire range of the piano.

Things you can do without buying another text book. Google and search Youtube to hear and see how the following key words will help you learn about music theory:

Chord construction

Scales

Modes

Arpeggios

...and get specific with adding 'accordion' to your search as well.

Answer 2

Stradella chord diagrams are a dime a dozen, and if your teacher can write down chords for you, you presumably know (or can look up) the relation between a chord name and the button.

So I'll focus on the specific relation of chord buttons to individual notes on an accordion, in order to answer the accordion-specific part of the question not easily found elsewhere.

Accordion bass/chord buttons have a lackadaisical relation with octaves and chord voicings: essentially they are being ignored.

The accordion mechanics map the Stradella chord buttons to 24 separate "notes", 12 bass notes and 12 chord notes. Almost all accordions automatically play the corresponding "chord note" along with whatever "bass note" is being played in order to have more full-bodied bass notes.

Almost all accordions play exactly 3 chord notes on each chord button. With 4 chord rows, the 4 chords in the C row are then spelled c=, cm=<c e♭ g>, c7=<c e b♭>, cdim=<c e♭ a>. If there are only 3 chord rows (because there are only 5 button rows all-in-all or because 3 rows are bass rows), they are spelled c=, cm=<c e♭ g>, c7=<e g b♭>. This means that with only 3 chord rows, the chord that is labelled c7 actually plays the notes that the system with 4 chord rows labels gdim.

Note that all this reckoning of notes completely ignores the octave relation of the notes in the chords and rely on equal-tempered tuning. So what octave do they actually come from? The answer is "it depends on the registration". An accordion has "reed banks" that have a range of 1 octave in the bass, and there are usually several reed banks. Common large accordions have 5 reed banks on the bass side, 2 for the chord notes, and 3 for the chord notes. Which of them are active, depends on the registration. Large Hohner instruments (though not their "Gola" top model line) tend to have bass octaves start from E1, E2, and chord octaves start from E3, E4, E5. Italian instruments are much more diverse, I have one with octaves starting at A1, A2, F♯3, C4, C5. When fully registering an instrument with such staggered reed banks, its bass notes utilising all 5 reed banks "wrap octaves" in different reed banks on different notes, giving the bass notes a comparatively "unordered" character where declaring one to be of higher pitch than another makes little sense and only the "functional" character of a particular note remains.

Typically, this "functional" treatment of chords and bass notes works best with full registrations that, for reasons of tonal balance with the treble side of the accordion, require playing bass and chord notes in a semi-staccato manner. When using registers with fewer reedbanks, the octave breaks become more obtrusive in bass runs and in the chord's voice leading. For example, the sequence b7-e on an instrument using only one reed bank starting at E3 may end up using notes A3-B3-D♯4 and E3-G3-B3 which has awful voice leading.

With regard to the actual chord buttons to be played, all those are "implementation details": that the chords have no dependable inversion tends to be comparatively unimportant musically when an accompaniment pattern of alternating bass and chord notes is chosen where the bass notes are of unspecific but lower octave than the corresponding chords: that tends to "ground" the chords properly.

Pressing chord buttons not matching the preceding bass button or pressing multiple chord buttons (possibly along with bass buttons) can produce more complex chords: those are quite useful for chords typically used in Jazz. However, that's a more advanced topic.

Answer 3

Almost all accordions (button or piano) have a Stradella Bass arrangement. Chords are layed out in a 6x20 or similar pattern. The "short" direction has several chords with the same root and the roots are traversed in the "long" direction. One direction (top of the accordion, closest to your face when playing) is row 6 and the bottom (near your feet) is row 1 (there may be extra rows or fewer but these are the main ones. (Or the other way around if I remember badly.)

Row 2 is the "root" row. Each button plays a single note (perhaps doubled at the octave depending on how many reeds the accordion has.) There is usually an indentation in the C button (to make it easy to find by feel.)

Just above row 2 is row 1 called the counter-bass row. It plays single notes a major third above row 2. Thus one can play walking or boom-chick bass lines or even a counter-melody on the first two rows. (A few accordions have an extra row (row 0, I guess) above this but I don't know what notes are used.)

Row 3, below row 2, plays the major triad with the row 2 note as the root. Its a three-note chord (perhaps doubled) using scale steps 1, 3, and 5. (C-E-G for a C bass.)

Row 4, plays the minor triad for the same root, steps 1, b3, and 5.(C-Eb-G)

Row 5, plays the "dominant seventh" chord with the fifth omitted. This is notes 1, 3, b7. The fifth is omitted to keep the chord density the same across types. Some accordion makers do just use different densities by keeping scale step 5. (C-E-Bb)

Row 6, plays the "diminished seventh" with the fifth omitted. The notes are scale steps 1, b3, and b6. (C-Eb-Ab) This also the Italian Sixth on C (used mostly in the key of E); adding (right hand, which I do, or counter-bass line on row 1) F# or F gives either the German or French Sixth which can be useful.

I have usually played the bass row with my 3rd (ring) finger and chords with the second (pointer) finger. Newer texts recommend using the 4th and 3rd fingers instead. There should be tutorials on the internet.