Why Don't Jazzpersons Use These Chords? Score and sound recording of a new piece.
Sunday, May 8, 2011 at 7:37PM

When I started teaching jazz harmony at Box Hill Institute, I became intrigued with those chords that were considered the “building blocks” of jazz, some of which I had been using in a non-jazz harmony context for many years – I'd used the “building blocks,” but not the “harmonic glue” - and wondered what some of them would sound like in just-intonation. For example, the dominant 7th with an added 9th, C E G Bb D, could be expressed with harmonics 4 5 6 7 and 9. After much fooling around, I came to a 12-note scale, based on C, of the odd numbered harmonics through 25, except harmonic 23. Harmonic 23 was eliminated because it would put too many pitches between C & G, resulting in my 3/2 being on Ab instead of G, and for this piece I wanted to use the normal 12-note keyboard with approximate normal harmonic relations (and fingering) for the key of C. The end scale was this:

But, of course, since this is just-intonation, if you play the same chord on different keys, it's going to sound different. Sometimes the differences will be subtle, and other times the differences will be great – a consonant chord transposed a minor second can become a grinding dissonance. To my ears, that's a good thing, but to the traditional world, that's probably not desired. Here's that same C E G Bb D chord played on all 12 fundamentals:


The use of a piano timbre makes the differences between each transposition level very prominent. Here's another example. The same scale, but a slightly different chord – the minor 9th – C Eb G Bb D, transposed to all 12 fundamentals.


 I found a chart of the 12 most common jazz 7th chords in a music theory book. To this list, I added a 13th chord (which was not a harmonic 13th chord), and added a major 9th to all the chords. I used these chords as "fingering templates" and applied them to the scale of odd numbered harmonics. I played the set of 13 chords 12 times, each time at a different transposition. Because of the unequal nature of the just-intonation scale, each transposition sounds different from the others – sometimes subtly different, sometimes radically different, revealing that in just-intonation there is the potential for much greater dissonance AND much greater consonance than 12-tone equal temperament provides. Or as Harry Partch said, dissonance in just-intonation is a “whole other serving of tapioca.”   

Once I'd done that, I realized I could turn the whole thing upside down and play it on the scale of subharmonics.  If you turn the scale upside down, you get a scale of subharmonics 1-25, without subharmonic 23. This scale, although inverted, has a lot of the same “sounds” as the harmonic scale. This inversion produces things that still sound like jazz chords, but which have a different colour than the harmonic-based chords. Here's the subharmonic scale:

I used an electric piano timbre for the piece. Finding the “right” electric piano sound was quite a task – I didn't realise the vast range of sounds that fit under the name “electric piano.” Finally, I made the sound I wanted, using Big Tick's “Rhino” synthesizer, and processing it through the Melda Production Multiband Reverb. The piece lasts 45 minutes. It's an exploration of a harmonic world that “might-have-been” or one that “might come to be.” Over the course of the piece, to my ears at least, the chords, even the most dissonant, cease having a quality of “strangeness” or “out-of-tuneness,” and simply become sounds in their own right. Which is what I hope would happen in this pretty yet unrelenting piece – the unusual sounds would become “normalised,” and a new set of harmonic resources would reveal themselves for those interested in hearing and playing them.

The SCORE can be found HERE.

Here's a recording of the 45 minute piece:


If you want to download it, just go to http://www.zebraandmoose.com/sounds/WhyDontJazzpersonsUseTheseChords.mp3.

Or, for a higher fidelity version, go to http://www.zebraandmoose.com/sounds/WhyDontJazzpersonsUseTheseChords.ogg.   

In Google Chrome, at least (I don't know about other browsers), a player will appear, and if you right-click on the player, you can download either file.

The title is a good natured teasing of my many jazz playing friends, but also an invitation to them. Here's a new harmonic world for you to explore! Enjoy!

Article originally appeared on WARREN BURT (http://www.warrenburt.com/).
See website for complete article licensing information.