Below you'll see a custom version of the SongTrellis Chord Grid, that lists only three chord types: the minor seventh (mi7), the dominant 7th (MA7) and the Major seventh (MA7).

The entire chord grid, with its 44 types of chords listed, can be a daunting beast because there are so many different kinds of harmonic sensation packed in there that's its difficult to understand the relationships between all of those different sounds

To make it possible to present grids that list with a tighter focus a smaller subset of chord types, there's a new gridTypes parameter that can be added to Chord Grid URLS.

To make a grid, that includes the three most important chord types of Major sounding harmony, it suffices to add

?gridTypes=MA7,7,mi7

at the end of the stock chord grid URL (http://www.songtrellis.com/chordGrid).

Now that you you have your own chord grid available that you can play with, I'll show you a few harmony experiments that you can perform for yourself in a few moments.

Try first experiment

First experiment:

Choose one of the three chord type rows in the grid, either the MA7 row, the 7 row or the mi7 row. Click on on every square in that row, starting with C over to G and then click back on the 'C' square a final time.

A second or so after you click on a grid square, SongTrellis will play you an instance of the chord type specified by the grid row you've chosen built upon the root name that labels the square you've clicked on.

A bit of Chord Grid coaching:
Every chord that chord grid plays for you will be performed under control of a MIDI player which is set to loop. Chord grid chord examples loop so that you can practice with the chord presented, without having to worry continuously about restarting it. You can stop the loop by pressing the pause button on the chord's controller.

If you are done listening to the last chord presented, simply click on a different grid square. The playback of the last chord will terminate as the new chord instance you've requested starts to play.

What sensations will you experience?

All off the chords that sound as you click across the grid row have a similar sound. They were all built using a similar formula, which accounts for the sound similarity.

There are twelve different chord roots that a particular chord type can be built upon. By clicking each square in the row you are hearing all twelve of the ways that chord type can sound as its built on the different roots.

The chord roots are arranged so that as you move from one grid square to its next neighbor, you will hear the chord of that type that is in some sense its closest relative. If you click on a square, and then click on the squares that are just to the left and to the right of it, your ear will experience an easy to understand (and extremely frequently heard) transition from one chord to its neighbor.

No matter which row you decide to travel across, you are likely to hear a pattern that gives you the sensation of walking down a stairstep. Every successive pair of chords, will seem to move down in your ear when you compare them with the previous chord pair.The amazing thing is that if you follow this cycle through any of the 44 chord type rows listed in the full chord grid, you will hear this same kind of chord motion at play in each.

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Second experiment:

Click on the C square at the beginning of a row. Then move to the G square on the far right and in sequence click on each square to the left until you click the C square again.

What will you hear?

Just as the overall sensation you experienced in Experiment #1 was of pairs of chords stairstepping downward, traveling in the opposite direction within a grid row produces a sensation of chord pairs stepping upward.

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A Name for what you heard

There is a fixed relation, an easy to calculate formula, which determines which chord roots are neighbors in this chord grid.

For any square that you choose, the root name on the right will be a perfect fifth interval below that square's root name.

The root name on the left will be a perfect fifth interval above that square's root name.

Following the sequence in either direction from any starting grid square, and jumping to the other side of the list and continuing in the same direction when the list runs out, spells out a cycle of twelve different chord root names. It's a cycle, because after you've visited all twelve possible roots moving in either direction, you'll return to the grid square you started with.

When you follow a grid row to the right, the next grid square name will always be a perfect fifth below the current square that you visit. When you visit all of the twelve possible chord roots by continually moving to the right, you are following the cycle of descending perfect fifths, which gives you the impression of pairs of chords that step down.

When you follow a grid row to the left, the next grid square name will always be a perfect fifth above the current square that you visit. When you visit all of the twelve possible chord roots by continually moving to the right, you are following the cycle of ascending perfect fifths, which gives you the impression of pairs of chords that step up.

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Third experiment:

If you choose a chord and make larger skips to the left or to the right, you will likely recognize the sensation of making those jumps but you will experience more and more of a mental twist as you try to make sense of what you are hearing and figure out how they are related to each other.

If you jump to a grid square that is six squares to the left or right of one that you choose, you'll be visiting it's farthest relative of that type. If you click on C and then click on the square that is six positions to the right, Gb, you'll hear C's most distant relative. If you start with C, jump to the end of the list and march backward six positions you'll see that you are visiting Gb again, having traveled in the opposite direction.

What you'll experience

As you skip to chords that are five, four, three, two, or one positions away, you are visiting chords that are more closely related, so you'll experience a smaller mental twist to comprehend those smaller jumps within the grid.

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Fourth experiment:

Click on any square in the mi7 row. Then in the column to the right, click on the neighbor square in the 7 row. Then in the column just to the right of your 7 chord choice, click in the the MA7 row. You've traced out a diagonal pattern that moves up one row and to the right.

Now that you've heard what that sounds like, choose a few different starting points in the mi7 row and run the pattern.

What will you hear?

Every time you run this pattern, you will hear the Chord Grid perform an instance of a chord progression which was a building block (and favorite harmonic cliche) of popular music and jazz during the fifty year period from the beginning of the 20th century up until 1960 or so. It's called the ii-V-I progression. (Click here to find out what it's name means)

When you heard the mi7 chord, you likely felt a certain medium level of activity or tension as it sounded. When the 7 chord played, you likely felt a rising level of tension, quite a bit more than the mi7 caused in your ear.

When you finally heard the MA7 chord, likely you felt that the tension level or activity level of that chord dropped considerably, and that your ear had arrived at a resting place after you had heard the higher tension contributed by the mi7 and the 7 chord.

Musicians call this kind of chord sequence a iimi7-V7-IMA7 progression, and usually use the the abbreviated name ii-V-I as a shorthand description for it. If you build a four note chord starting on each scale step of a Major scale and skip every other note moving upward from that root, we find that the chord that's built above the second scale step (signified by the roman numeral ii) is a mi7 chord, the chord built on the 5th sale step (signified by V) is a 7 chord, and the chord built on the scale root (signified by I) is a MA7 chord.

Since descending from scale step ii to scale step V forms a descending Perfect 5th interval, and since descending from scale step V to the scale root I likewise forms a descending Prefect 5th interval, our upward and to the right pattern of chords through this chord grid spells out individual ii-V-I patterns for each of the 12 possible Major scales that contain the the I chord that is the destination of each progression.

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Fifth experiment:

In experiment four, you clicked in an upward and to the right diagonal from mi7 to 7 to MA7 after choosing a random starting point in the mi7 row.

This time start the diagonal, moving from mi7 to 7, but don't continue immediately to the MA7 row. Instead retrace your clicks through mi7 and 7 several times. Finally, when you wish to stop, click on the MA7 square at the end of the up and to the right diagonal to complete the pattern.

Example: if you decided to start on B, you would have repeatedly clicked on B in the mi7 row, followed by E in the 7 row, before you finally ended with A in the MA7 row.

What will you hear?

In this case, your ear was a little disappointed whenever you played the 7 chord and did not immediately follow it with the MA7 chord. You had an expectation that this should happen.

When you backtracked to mi7 each time to restart the pattern, it was like someone had repeated the first part of a saying or proverb that you'd heard hundreds of times, but did not utter the last word.

When you finally did allow the MA7 chord to play, you likely had a strong feeling that an interrupted pattern had been completed.

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Sixth experiment:

The interrupted mi7 down a perfect fifth interval to 7 chord' patterns that we heard in the last experiment, actually can be torn free from the MA7 chord that we expect to hear descend by perfect fifth after the 7 chord, and can be used as a building block to build patterned harmony with greater interest and greater color that continues through a larger number of chord stops, producing a longer chord progression.

Try these moves:

Click on Gmi7 to C7, Cmi7 to F7, Fmi7 to Bb7, Bbmi7 to Eb7, Ebmi7 to Ab7 to DbMA7.

What this will do is start the upward and to the right pattern on each square of the mi7 row moving to the right after each use of the pattern. After the last pattern, the Ebmi7 to Ab7, we continue to the DbMA7 that we expect to usually hear after a Ebmi7-Ab7 sequence is played.

Next, click on Gmi7 to C7,Fmi7 to Bb7, Ebmi7 to Ab7, Dbmi7 to G7, Bmi7 to E7 to AMA7.

This time we are starting on the Gmi7 square and skipping one square to hit the one two squares to the right each time to continue the pattern. After the last usage of the pattern Bmi7 to E7 we continue one square to the right to pick up the AMA7 we expect to hear to terminate that pattern.

A third pattern: click on Gmi7 to C7,Bbmi to Eb7,Dbmi7 to Gb7,Emi7 to A7, ending with DMA7. Here we are deploying the 'up an to the right' pattern to generate ii-V patterns, and are skipping two columns before we start the next ii-V pair.

A fourth pattern: click on Gmi7 to C7, Ebmi7 to Abmi7, Bmi7 to E7, ending with AMA7. Now we're skipping three columns before we start the next ii-V pair.

A fifth pattern: click on Gmi7 to C7, Abmi7 to Db7, A7 to D7, Bbmi7 to Eb7 to AbMA7. Now we're skipping four columns to the right before we start the next ii-V pair.

A sixth pattern: click on Gmi7 to C7, Dbmi7 to Gb7 to BMA7. This time we've skipped five columns to the right before we start the next ii-V pattern.

What did we hear?

We discovered that using a iimi7 to V7 progression as a building block, if we skipped a constant distance around the grid before starting the next pattern, we would create a progressions that made sense, which produced a different musical effect depending on the size of the skips that we used.

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