Minor nitpick: It’s not a sus – Cm add 9 (or 2) is correct, like you had it initially. With a sus chord, the suspended note takes the place of the third, making tonality ambiguous. Dropping the C doesn’t affect this.
Ah ok thanks.
I’ve really enjoyed the clips you guys have put up, thanks.
That’s a trick I’ve used to add a bit of additional harshness. When the m(add2) is voiced as a simple block chord, that minor 9th (between the 2 and 3) gives you a bit of a cluster sound without overriding the feel of the minor chord. And, if you make it the tonal center, and later contrast it with the relative or parallel major, the juxtaposition can be quite powerful.
It’s my sister’s favorite chord, as she loves the simplicity and the dissonance.
Steely Dan called those types of chords “mu” chords (pronounced “moo.”) For the most part, they did it with major chords, but “mu minor” chords exist. The voicings can vary, but the main feature is that the add9 and third exist in a cluster against one another in the chord. (So, voicings like 1-2-3-5 and 1-5-2-3, for example, but the root could be an octave down. I’m not sure how dogmatic they were about always having the second rub up against the third, but I think it was part of whatever definition they had for it. “Mu chord” is their terminology, not any official musical term used in Western theory.)
Pop songs are full of add9s (or, like I’ve said before, some people prefer calling them add 2s, depending on how they’re voiced) to major chords. I also find a lot of soul and R&B, especially with electric piano sounds, loves that type of chord, and with even more “smudge” to it (i.e., tone clusters up the wazoo, with technique of smearing two adjacent notes together with one finger, often the thumb.)
The “mu minor” chords I don’t see quite as much, for some reason. To me, like I said above, the effect of these chords is to make them sound a bit more complex without the baggage of adding a seventh of some flavor to them. It adds color and dissonance without sounding too straight-up jazzy. I kind of consider it a “pop” sound, for some reason. With a minor chord, it sounds more haunting, more mysterious. With a major chord, it sounds “fuller” and more “colorful” to me.