Q: What is a chord harmonica?
A: As an extension of the more general discussion in part 1 and from "Re: Chord (another digression)" 30 Aug 1994 GM:
There are two styles of chord layouts which Hohner has produced though the years +/- a couple of years is before and after 1940. The "new" chord is designed according to the circle of 5ths (from left to right). It is two harmonicas, hinged together. Each chord consists of 8 reeds. There are 5 types of chords on the instrument: major, minor, dominant seventh, augmented and fully diminished seventh. For every major chord that you blow on the upper harmonica, you will draw its dominant seventh. For every minor chord that you blow on the bottom harmonica, you will draw either an augmented dominant, or a fully diminished seventh dominant. For example:
Upper blow: C Major G Maj D Maj A Maj E Maj Upper draw: G Dominant 7th D 7th A 7th E 7th B 7th
Lower blow: C Minor G Min D Min A Min E Min Lower draw: G Augmented D Dim A Aug E Dim E Dim
Now since each of the 6 augmented triads can function in 3 different keys, there are two duplicates and since each of the 6 diminished seventh chords function in 4 different keys, there are 3 duplicates. For instance, above might seem that I have made a mistake, an E dim below the E min, but it is not a mistake. You would expect a B dim in that position.
The 6 diminished chords are Ab, Bb, C, D, E Gb. Look at their spellings:
PROPER SPELLINGS ENHARMONIC SPELLINGS Duplicates 1.) Ab dim: Ab Cb Ebb Gbb Ab B D F 1.) 2.) Bb dim: Bb Db Fb Abb Bb Db E G | 2.) 3.) C dim: C Eb Gb Bbb C Eb Gb A | | 3.) 4.) D dim: D F Ab Cb D F Ab B 4.) | | 5.) E dim: E G Bb Db E G Bb Db 5.) | 6.) Gb dim: Gb Bbb Dbb Fbb Gb A C Eb 6.)
Look at the similar notes in 1 & 4, 2 & 5, and 3 & 6. Each of these chords can function as though any one of its notes were the root.
The 6 augmented chords are A Bb Db Eb E G. Look at their spellings:
PROPER SPELLINGS ENHARMONIC SPELLINGS Duplicates 1.) A aug: A C# E# A Db F 1.) 2.) Bb aug: Bb D F# Bb D Gb | 2.) 3.) Db aug: Db F A Db F A 3.) 4.) Eb aug: Eb G B Eb G B 4.) 5.) E aug: E G# B# E G# C | 5.) 6.) G aug: G B D# G B Eb 6.)
As you can see, there are not as many direct duplicates here -- "Re: Chord (another digression)" 30 Aug 1994 GM
Also from "Chord and Bass Layouts" 30 Aug 94 WY:
The chord has a two-tiered layout with hinge, like the bass. It is also an octave-tuned double reeded instrument, but it has both blow and draw notes, which produce different chords. The chords are arranged in the cycle of fifths (they used to be different, but I don't know the details. While watching Al Smith and Alan Pogson both playing chord on-stage together at the SPAH convention, they kept moving their instruments in opposite directions. I thought maybe one guy played upside down, but it turned out they had different vintage instruments with different chord layouts).
Here is the current (I think) layout for the chord:
BLOW Gb Db Ab Eb Bb F C G D A E B TOP DRAW Db7 Ab7 Eb7 Bb7 F7 C7 G7 D7 A7 E7 B7 F#7
BLOW Gbm Dbm Abm Ebm Bbm Fm Cm Gm Dm Am Em Bm BOTTOM DRAW Db+ Ab@7 Eb+ Bb@7 Bb+ C@7 G+ D@7 A+ E@7 E+ F#@7
In the top row the draw and blow chord in each location form a V7 and I relationship, just like on the lower part of a diatonic.
In the bottom row, we have minor chords instead of major, with the same chord roots, so you could still play a V7 - I by drawing and blowing in the same horizontal location, but you would have to switch rows to get the minor chord.
The draw chords in the bottom row alternate between augmented (+) chords and diminished 7ths (@7), with the same chord roots as the draw chords on the upper row. Augmented chords often are used as a different color of V chord, so they're fairly well placed as draw chords. The diminished are a little more tricky, and very versatile (I won't get into that now).
Now, we have twelve of every other kind of chord, but only six each of augmented and diminished. But there are really only four unique augmented triads, and only three diminished sevenths, if you discount duplicate spellings (C-Eb-Gb-Bbb = A-C-Eb-Gb, for instance, and G-B-D# = Eb-G-B). So actually having six of each gives us some duplications to work with (A+ = Db+, Eb+ = G+) (Ab@7 = D@7, Bb@7 = E@7, C@7 = F#@7).
Some chord players block out notes to alter chords, and some have mastered the art of playing two chords, or parts of two chords, together to create a more complex chord.
All kinds of tonguing effects are also possible. -- "Chord and Bass Layouts " 30 Aug 94 WY, "Re: Chord and Bass Layouts" 31 Aug 1994 GM