When Discussing the progess of this thesis with my mentor and teacher Anders Jormin, he kept coming back to the importance of keys. Keys are always a factor to consider when approaching a composition as a bass player, as there are "easier" and "harder" keys on the bass. Keys containing one ore more of the following notes - E, A, D, and G - are ususally considered "easier" to play as the bass player has a reference point for intonation in the open strings. When it comes to harmonics, the same principal applies. As you may have noticed from the harmonics chart above there are several notes from the chromatic scale missing. This posed a serious issue for me - in fact, it made me question the very question I was reseaching: Is there a viable way to use the bass as a chord instrument? To make visible which notes are missing, I wrote down the chromatic scale below, marking playable harmonic note names as Bold and unplayable ones as Italics.
A, A#/Bb, B, C, C#, D, D#/Eb, E, F, F#/Gb, G, G#/Ab,
Since I was content with how the notes of the harmonic chart sounded (even though I knew there were notes in the overtone series that were technically unplayable) I was at an impasse. How could I present a method proclaiming that the upright bass was now a fully functional chord instrument if the method was dependant on certain keys?
After giving the matter some thought, and excluding tuning the bass in anything but fourths, I finally came to the conclusing that even though it is impossible to play any harmonic in any given situation without time to prepare, one can indeed prepare the bass by tuning all strings one half step down or up. This is called Scordatura (italian for mistuning, or retuning)
Doing this gives access to two new versions of the chromatic scale which, if applied to the harmonics chart, would look like this:
Half step up from EADG (E#A#D#G#)
A#/Bb, B, C, C#, D, D#/Eb, E, E#/F, F#/Gb, G, G#/Ab, A
Half step down from EADG (EbAbDbGb)
Ab/G#, A, A#/Bb, B, B#/C, C#, D, D#/Eb, E, E#/F, F#/Gb, G
Using this method allows the bass player to, with some time to prepare, be able to use all notes in the chromatic scale as harmonics to complement root notes as upper structure. A demonstration of this "prepared bass" can be found to the right, which is a video of myself and pianist Antti Lähtesmäki playing the standard Footprints by Wayne Shorter in Cm. The bass is tuned one half step up, allowing me to play the traditional bass line using only harmonics.
As a sidenote I would like to add that this method disregards the use of artificial harmonics. Any note can be played as an artificial harmonic and as such isn't limited by the rules natural harmonics has to abide by. Artificial harmonics are, however, more difficult to utilize since they require three points of contact with the string as opposed to the natural harmonics, which only requires two.