Tuning for Double Chromatic: Fully chromatic slide diatonic spiral with all the chords!

Anything apart from the two mainstream default harmonicas (Solo-tuned fully-valved chromatic, and un-valved Richter 10-hole diatonic). Alternate tunings, different construction, new functionality, interesting old designs, wishful-thinking... whatever!
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EdvinW
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Location: Sweden

Tuning for Double Chromatic: Fully chromatic slide diatonic spiral with all the chords!

Post by EdvinW » Thu Dec 12, 2019 2:36 pm

A spiral tuned harp has all the standard triad chords in its key, three major chords and three minor chords. Thus, it covers the major chords of one quadrant of the circle of fifths plus their minor parallels, one fourth of all the common chords.

The following tuning for Brendan Power's twin chromatics consists of four spiral tuned plates in keys Eb, C, A and F#, together covering all 24 minor and major triads.

Code: Select all

      Slider a+b  E# G# B  D# F# A# C# E# G# B  D# F# 
      Slider a    D  F# A  C# E  G# B  D  F# A  C# E 
Blow: No Slider   C  E  G  B  D  F  A  C  E  G  B  D
      Slider b    D  F  Ab C  Eb G  Bb D  F  Ab C  Eb
      
Hole:             1  2  3  4  5  6  7  8  9  10 11 12

      Slider a+b  F# A# C# E# G# B  D# F# A# C# E# F# 
      Slider a    E  G# B  D  F# A  C# E  G# B  D  F#
Draw: No Slider   D  F  A  C  E  G  B  D  F  A  C  E
      Slider b    Eb G  Bb D  F  Ab C  Eb G  Bb D  F 
Except for covering all the chords, with this choice of keys any key could be played within one of the spirals and at most one note from another spiral.

The spirals are shifted so that pushing a slider not only changes the key signature, but also takes you to the next note of the scale like a slide diatonic.

The key of C has diatonic slide decorations at every note, and most other keys have them at all but one or two notes.

So to describe it with a few basic selling points:
* Chromatic!
* All the chords!
* Any key with at most one slider note!
* Acts as a slide diatonic in most keys!
Edvin Wedin

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Brendan
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Re: Tuning for Double Chromatic: Fully chromatic slide diatonic spiral with all the chords!

Post by Brendan » Fri Dec 13, 2019 11:35 am

It seems Spiral/Circular tuning variants are capturing the attention of some clever theoreticians in this forum recently.

This is a cool one Edvin! Now I just need to create the good playable DoubleChrom to allow it to be realised. Happy to say I'm making good progress on that, will keep you posted.

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IaNerd
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Re: Tuning for Double Chromatic: Fully chromatic slide diatonic spiral with all the chords!

Post by IaNerd » Mon Dec 16, 2019 12:42 pm

This reminds me of a related concept. In some tunings of some Electronic Wind Instruments (EWIs), one special key will raise the pitch by two semitones, and a different key lowers the pitch by one semitone. Pressing both gives the additive effect of raising the pitch by one semitone.

EdvinW
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Re: Tuning for Double Chromatic: Fully chromatic slide diatonic spiral with all the chords!

Post by EdvinW » Fri Dec 20, 2019 12:24 pm

@Bendan: Well, for tunings with lots of chords the spiral is hard to avoid :)

@IaNerd: It's not so much additive as selective. Pressing just Slider 'a' raises half the notes, pressing also Slider 'b' raises the other half, except for the B. A person accustomed to a slider that raises every note half a step could thus feel more at home manoeuvring the two sliders as one.

This becomes clearer in the following variation of this tuning without the slide diatonic effect. They contain spirals in the same keys, just not shifted in the same way.

Code: Select all

      Slider a+b  C# E# G# B  D# F# A# C# E# G# B  D# 
      Slider a    C# E  G# B  D  F# A  C# E  G# B  D 
Blow: No Slider   C  E  G  B  D  F  A  C  E  G  B  D 
      Slider b    C  Eb G  Bb D  F  Ab C  Eb G  Bb D 
      		  				   
Hole:             1  2  3  4  5  6  7  8  9  10 11 12
		  				   
      Slider a+b  D# F# A# C# E# G# B  D# F# A# C# E# 
      Slider a    D  F# A  C# E  G# B  D  F# A  C# E 
Draw: No Slider   D  F  A  C  E  G  B  D  F  A  C  E 
      Slider b    D  F  Ab C  Eb G  Bb D  F  Ab C  Eb
Slider A raises F, C and G; slider B lowers A, E and B; and combined the sliders raise all notes but B.

In many of the flat keys, there are several diatonic slide decorations available in this tuning as well. In Eb, for instance, diatonic slider trills can be played at notes Ab, D, Eb and G. Some additional whole-note trills can be obtained by combining a slider push with a jawflick, i.e. alternating between 4D(a+b) and 5D(b).

Because of the observations in the previous paragraph, for most forms of traditional music it probably makes sense to transpose this from C to A, E or B.
Edvin Wedin

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