"C central" note layout

This is one more chapter of the saga about my search for the ultimate
Chameleon note layout with Carlos Gamma tuning system.

Previous chapters are:

Chameleons in the dark

Gamma Chameleon Notation

Adagio Gamma revisited

Gamma Elegy

Tetrachordal Gamma

Gamma Monk and the Semitones

“A central” note layout

This new layout is a variation of my previous one (“A central” ) that I have created following this basic idea: to find a common way to notate Carlos Gamma on both an
Halberstadt keyboard and an isomorphic one.

Lately I have been using either my digital piano with a dodecatonic mode of Carlos Gamma or my Chameleon with a full Carlos Gamma note layout, so the question is: is there a common way to notate music that can be applied to both keyboards even though they do not share the same layout?

If you go back to my “Adagio Gamma Revisited” article you see that, at the time, I thought I had to “trans-notate” a piece of music originally played on a standard keyboard to be able to play it with my Chameleon but I was wrong.

I devised the following MIDI system to prove that my intuition about solving the above question was possible. Look at this diagram:


The Chameleon sends its MIDI data, through a MIDI interface, to my MacBook Pro.
Disarray, an application written by X.J.Scott, remaps the Chameleon’s note layout and sends the output to LMSO, another application written by X.J.Scott (God bless him!). LMSO retunes notes according to Carlos Gamma tuning system (20th root of 3:2).


Its output goes, through LMSO IAC to
Logic Pro, from where it can be sent wherever I want.

(IAC stands for inter-application MIDI communication)

Nord Stage 88 (used as a MIDI controller) also sends its MIDI data to the MBP. Its output goes to LMSO that retunes notes to the following dodecatonic mode of Carlos Gamma:


The following one is a screenshot of LMSO. On the left you can see the “box” receiving data from the Chameleon/Disarray, on the right you can see the one receiving data from the NS88.


In order to validate the rightness of my layout I created the following Logic Pro’s environment layer:


I proceeded playing single notes on the NS88 looking at the MIDI data coming from it and checking if their position on the Chameleon was where I expected them to be. To make sure I was playing the same pitch I looked at the monitor. In the above case you see that I play C3 with no pitch bend (0 64 value) on both keyboards.

This is the Chameleon’s layout :


The red button is the “anchor key”, “prime unity” of both layouts.

The 7 columns of white buttons correspond to the white keys of the NS88.

The 5 columns of green buttons correspond to the black keys of the NS88 (notated as “sharps” ).

The buttons without labels are outside the MIDI range.

So, as long as I play within this area of white and green buttons (on the Chameleon) I can switch from one MIDI controller to the other and play the same notes using the same standard notation but, of course the sonic results are not those of a regular keyboard tuned to 12tET, so, for example, keys C3 - C4, on both keyboards, sounds the same perfect fifth (3:2) interval, keys C3 - F#3, on both keyboards, sounds the same major third (5:4) interval, keys C3 - F3, on both keyboards, sounds the same minor third (6:5) interval (see note chart below).

I find this layout very interesting and useful!

The 8 blue and yellow columns are notes that appear only on the Chameleon. The blue ones are notated as “flats” and the yellow ones using a different notehead.

To understand what really happens “behind the scene” look at the following diagram: inside each button you see the MIDI message sent when it gets depressed (MIDI note name, octave, pitch bend value). As you can see, only C3 has a pitch bend value of 0 64 (no pitch bend).
Compare this diagram with the previous one.


Each corresponding key of the NS88 would generate exactly the same MIDI message (with the exception of notes on blue and yellow columns that do not exist on it).

Someone could ask: why different layouts on the 2 MIDI controllers?
A full Carlos Gamma layout on an Halberstadt keyboard is highly impracticable so it is better to use a good approximation of it that nicely fits within its 12 note pattern. On the other hand it would be a sacrilege to have a fancy isomorphic keyboard like the Chameleon and not take advantage of its features that make a full-fledged Carlos Gamma layout “manageable”.

In the end I would like to show how Carlos Gamma appears with the new note layout on the Chameleon:


and how it looks on a Halberstadt keyboard (using the above mentioned dodecatonic mode):


if we extend the Carlos Gamma pattern beyond 3:2 up to a compressed/stretched octave on the Chameleon we get:


and on a Halberstadt keyboard (using the above mentioned dodecatonic mode):


JI intervals based on “
Anatomy of an Octave” by Kyle Gann

Video examples will follow shortly!


Check the
Double Trouble videos up!