How do I play lattice scales from the PC keyboard or use it as a Janko keyboard?

Introduction and motivation
The PC keyboard is very conveniently set out with a basically hexagonal, or honeycomb type layout. You will see that the keys run in three directions - the horizontal rows, and diagonally up to right and to left. This makes it ideal for exploring lattices or the innovative Janko keyboard layout.

Lattices
You have one interval running horizontally, one common choice is the major fifth 3/2. Then another interval is used for the diagonals - perhaps as you go up diagonally to the right you go up in pitch by a major third - then if you set it up like that - it turns out that as you go down diagonally up to the left, you go down by a minor third. With this layout, if you play two adjacent keys in the same row, and add in the key in between them in the row above, you will get a major triad. This works anywhere on the keyboard - you always get the same chord when you use that particular pattern, shifted in pitch. With this same pattern, if you play two adjacent keys, and add in the one between from the row below, you get a minor triad. Again you get the same chord with this pattern, anywhere on the keyboard.

That particular layout gives you a just intonation lattice which is especially interesting for exploring pure ratio type intonation and sequences of chords, but perhaps not that useful if you want to use it to play a particular tune, say. However, there are many other layouts you can explore using tone / semitione type tuning systems, which you can use to play tunes and conventional music.

Janko keyboards
A very common layout is to have whole tones running horizontally, and semitones diagonally. This is the Janko layout, which lets you play conventional major and minor scales very easily.

The nice thing about this style of keyboard is that you only ever need to learn one fingering for any chord or scale. There is one fingering pattern which will play all the major scales in any of the keys - including the nineteen major scales in in nineteen equal, or the thirty one major scales in a thirty one equal and so on. This is an approach that was first developed for twelve tone pianos in the nineteenth century by Paul Janko and pioneered by Liszt and Rubenstein - but for some reason despite their endorsement, it never really caught on at the time. However, you can see how it has even more advantages in microtonal systems with many more steps to an octave, and the idea has been kept very much alive by microtonalists. It also has been an inspiration for several new electronic keyboards which have gone on sale in recent years. To find out more about this type of keyboard, and it's history, you can start at the Wikipedia page about the Janko keyboard, or search on-line for Janko keyboard.

Limitations of the PC keyboard
Unfortunately the PC keyboard isn't ideal for this approach. You will find that some triads play fine, but with other combinations of keys on the keyboard some of the notes of the chord will fail to sound (at least, on all the keyboards I've tried).

Never mind though, you can still play all the triads by using a sustain pedal - or use the option to treat the space bar as a sustain, and you can get used to the eccentricities of a paritcular keyboard. Another way you can get around some of the limitations is to use two computers or laptops and play the PC keyboard on both simultaneously, one for the left hand and one for the right hand.

How to set up your PC keyboard like this in Tune Smithy
Okay, that's the motivation. Now for the practicalities - pretty easy really. Look for this icon in the main window:

Play from PC keyboard http://robertinventor.com/software/tunesmithy/help/pckbd_icon.gif

A click on this will bring up the PC keyboard player. You can also bring up the PC keyboard player at any time using Ctrl + K (or Ctrl + 112 ).

To configure the player, click on the To Play button to bring up the Notes to play for PC Keyboard keys Ctrl + K2 (or Ctrl + 24 )

Look for the button Make lattice or Janko (changes main scale)

Before you use the button, you need to choose which intervals you want to use for the horizontal and diagonal intervals. You set these in the text box below the button. For instance to try out the major and minor chords layout, choose 3/2 6/5.

To try out the nineteen equal layout choose @@3//19 2//19@@ - this will set the horizontal interval to three steps of nineteen equal - the nineteen equal whole tone, and the diagonal interval to two steps - the larger diatonic semitone. The other diagonal will play one step of nineteen equal, the smaller or chromatic semitone (e.g. C to C# or C# to Db).

Other presets can be used to explore the seventeen equal and thirty one equal Janko layouts, or various interesting pure ratio type lattices, and you can make more of your own following the same format. For more about this see the Hexagonal lattice help for this window in the Tune Smithy manual.

Displaying the notes appropriately
You will want to set the keyboard player to display the notes appropriately for your chosen lattice. To do that, use the To Show button in the Player window. This will bring up the What to show on PC Keyboard pics, sustain & controller window - Ctrl + K1 (or Ctrl + 123). Then you can select how you want to show the notes using the Show drop down list in this window.

For the ratios based systems then you can select Ratios from the drop down. Or to configure it in other ways - for instance to show cents, frequencies in hertz or whatever, set it to Anything Else - current notation for scales - and use the Current Notation.. button to configure exactly how you want to show the intervals.

For the nineteen or thirty one tone systems you may want to choose Note names from the drop down, then choose an appropriate system from the drop list. For instance nineteen tone notation will give you distinctions of sharps and flats as suitable for the nineteen tone system, also show the "extra notes" such as E# / Fb of nineteen equal. You can further configure how the notes are shown using the Note names as drop down.

Dealing with wide ranging keyboard pitches
Depending on the layout, the keyboard may span a large pitch range. For instance this happens if you use 3/2 for the horizontal interval - then the keyboard will span a little under seven octaves (from 1/1 to 1594323/128000). There are two ways you can deal with this.

If you go to the Parts window, then you can transpose the keyboard part down in pitch - highlight the first part there (or whichever part you want the PC keyboard to use) and transpose it down by three octaves (say) by setting the Octave shift to -3. The PC Keyboard Player normally uses whichever part is currently highlighted in the Parts window. You can change that in the To Play window (Ctrl + K2 ). Or if you want to transpose all the parts down in pitch - highlight them all and set the octave shift - or use the Pitch window (Ctrl + 10).

The other thing you can do is to use the Note Ranges window (Ctrl + 22). Highlight the part you want to adjust and set the highest and lowest note you wish to use for that part.

At times when you work mainly with the PC keyboard you may want to use the Mouse & Pc Keybd Music task which you will find in the purple Tasks for Tune Smithy 3 folder on your desktop. You will find the droplist of presets includes some lattices.