Re: [Harp-L] Chromatic Harmonica note arrangement



"Straight tuning"
Traditional and original arrangement.
Shorter slide movement...equal to half the spacing between holes.
More openings in the slide...two for each mouthpiece hole. One of them is active while the other is hidden behind the partition between holes.
Easier to understand when tuning or working on the harp.
From my point of view, the arrangement that makes the
Hands-Free-Chromatic possible.

"Cross tuning"
More recent arrangement.
Fewer openings in the slide...one for each mouthpiece hole. Easier to manufacture.
A slide opening moves all the way to an adjacent hole when the button is pushed.
Longer leakage paths between openings in the slide and thus less leakage at a given clearance.


Although the rectangular openings in a CX12 slide are larger than the ones in a 270 slide, two of their corners are covered by the round holes of the mouthpiece. The result is that the flow area in both harps is virtually the same...about .03 sq in. (19 sq mm) The air flow is primarily limited by the reed and slot. The majority of drop from your mouth pressure to atmospheric pressure occurs there. The amount and difference in pressure drop across the openings in the slide with slightly different areas will be imperceptible. Thus, cross-tuning does NOT provids "more air" to the reeds.

The player will blow/draw the amount of air through the reed that produces the desired response. Even if you increased the opening in the slide, this would only result in an imperceptible reduction in applied mouth pressure to attain that flow.

It boils down to a trade-off between short slide movement and less leakage through the slide. You pays your money and you takes your choice.

Vern

----- Original Message ----- From: "Harvey Berman" <cscharp@xxxxxxxxxxxxx>
To: <harp-l@xxxxxxxxxx>
Sent: Tuesday, November 17, 2009 9:34 PM
Subject: [Harp-L] Chromatic Harmonica note arrangement



I am mostly a diatonic player, though I have several Chromatic Harmonicas. Since I have been pretty successful at optimizing diatonics, for myself and my harp playing friends, I decided to tackle one of my Chromatics. So, I have what is probably a stupid question for one of you Chromatic experts. Why do some Chromatic harps have all the notes for the major scale of the key of the harp on the top plate, and the half step higher scale on the bottom plate, while other harps alternate the plates between notes?


If this doesn't make any sense let me phrase it another way. Why do some slides have the holes in a straight row, and other stagger the holes?

I assume that it has something to do with round holes vs square holes, since my Super 64 and CX 12 are staggered, and my 260, 270, and Meisterklasse, and Koch have straight holes. Does anyone know the answer?

I am just curious.

Thanks

Harvey Berman
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