Generally speaking, minor triads or three note chords sound sadder than major triads. In a sense, these two families of triads play off one another in helping to alter moods of any given composition that they are involved in. If you are playing a moody piece written by a non-medicated, bipolar composer, your accompanying chords will probably change from major to minor every second! Not to worry though. There probably aren’t too many of these types of compositions around.
Here is a list of the twelve possible root position minor triads available on a piano. A root position triad uses the first (tonic), third (mediant) and fifth (dominant) degrees of a minor scale. These degrees are played at the same time to form a triad:
C, Eb and G C#, E and G# D, F and A Eb, Gb and Bb E, G and B F, Ab and C F#, A and C# G, Bb and D G#, B and D# A, C and E Bb, Db and F B, D and F#
The bolded letters on the left are the lowest sounding in the triad. If you wanted to add some color to these triads, a fourth note could easily be added to the top of each of the triads at a distance of three semitones higher than the dominant, creating a minor seventh chord.
Counting by semitones means counting by the smallest distance between two particular notes on a piano. Thus, in the first above triad (C, Eb and G), a note three semitones above the G, the dominant, would create a C minor seven (Cm7) chord as follows: C, Eb, G and Bb. The Bb is three semitones higher than the G.
So why are these types of chords called minor seventh chords? Well, the triad is minor and an added fourth note sits seven letters higher that the lowest note of the chord (C, D, Eb, F, G, Ab, Bb… from C to Bb inclusively, there are seven letters). Have a look at the group of minor seventh built from the above minor triads. The bold letters indicate the added fourth note:
C, Eb, G and Bb D, F, A and C Eb, Gb, Bb and Db E, G, B and D F, Ab, C and Eb F#, A, C# and E G, Bb, D and F G#, B, D# and F# A, C, E and G Bb, Db, F and Ab B, D, F# and A Other more complex textures involving minor chords include minor ninth, eleventh and thirteenth chords. These types of chords can produce jazzy harmonies. For instance, a simple Cm7 chord (C, Eb, G and Bb) can be enhanced and arranged as such: Bb, D, Eb and G in the middle of the piano with the right hand, combined with a low C in the left. We now have a jazzed up Cm9 chord.
In the above chord, a different instrument often plays the low C for added color, thus freeing the pianist’s right hand for improvisational purposes. In this case, the Cm9 chord of Bb, D, Eb and G would be played with the left hand.
Try to recognize them the next time you are playing. They are very useful and using the variations shown, can really spice up your music making.