In this post I will be showing you how to make chords with extensions and how to read them. You will also find a table with examples of common chord extensions, that you are likely to come across, together with the interval relationships for building that specific chord over that root.
All the notes that are not the root, 3rd, 5th and 7th degrees of a given chord are called extensions. That said, there are only three extensions left to stack before we return to the root – the 2nd or 9th; the 4th or 11th; and 6th or 13th.
Notice that I included the simple and compound interval relationship between the root and the remaining extensions. Each type of chord extension will have a distinct feel and it can be used to add richness and depth to your music. Also, extensions introduce a certain tension in the harmonic progression which can also be used to lead or resolve to the next chord:
One thing to be aware of is that chord extensions change their relative intervallic quality according to the position of the chord root in the scale or mode it refers to, and thus are spelled differently – they can be sharpened (#11 or #9), flattened (b9, b13) or natural (11, 13, 9), even though we are on the same scale. For instance, if we consider the C major scale that has no sharps or flats, the 11th of Dm is natural because it’s based on a perfect fourth between D and G, and thus is spelled like Dm11; while the 11th of F major is spelled F maj#11 because it’s based on an augmented fourth between F and B:
Here is a table with the most common chord extensions and their spellings. It is not by any means a comprehensive list of all the possible extensions combination but hopefully it will shed some light on how chords may be spelled according to its extensions:
Keep in mind that when you see a chord spelled like C13, it means that the previous extensions are implied in the chord formation – the 9th and 11th. Also, in this case, this implies a dominant chord with minor 7th and if you want to indicate that the chord has a major seventh then you will need to write Cmaj13. Also, the prefix “add” means that the following extension is added to the chord without implying the previous ones. For instance, a Cm add11 only adds the 11th to the Cm chord without implying the 7th or the 9th.
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