Overblows, valves etc
RANDY - "valves" are otherwise known as "windsavers". They are used in
chromatic and chord harmonicas, accordions, concertinas and the like to
overcome inherent weaknesses in the design. In all these instruments,
both the blow and draw reeds for a given hole are mounted on the same
plate, which gives rise to considerable air-loss through the reed that
isn't being sounded - far greater (for some reason) than what you get
on a blues harp. The valve is glued to the opposite side of the plate
to the reed, but at the same end of the slot, and closes when the
"opposite" reed is being sounded, thus ensuring that all the air goes
to the reed that you want to sound. The best way to understand this is
just to take the covers off a Hohner 270 and play it in front of a
mirror - you'll be able to see the valves on the blow reeds opening and
closing. The valve itself is a strip of some flexible substance -
originally leather, now usually some kind of plastic, that is just
bigger all round than the slot that it covers.
The reason for fitting them on blues harps is that if you get
your technique right, you can play a full chromatic scale without
needing overblows, but as with anything else and harps you make a
series of compromises to achieve this (mainly tonal, it must be said -
though you *can* overcome this with practice).
All the holes where the draw note is higher in pitch than the
blow note have draw bends of some sort available, right? And all the
holes where the blow note is higher than the draw note have blow bends
of some sort available. So what you do to give a full chromatic scale
over the harp is to put valves on the *inside* of the draw plate in all
the holes where you can get draw bends, and on the *outside* of the
blow plate in all the holes where you can get blow bends. This takes
the length of the opposite reed out of the equation, enabling you to
play chromatically. As I say, it takes a good deal of practice to even
out the tonal differences that result - but as I said in my last post,
it's sometimes the only way to go.
It's also worth mentioning that the guy who got Suzuki to put
valves on the ProMaster range (Brendan Power of New Zealand) doesn't
use the valved bent notes as notes *as such*, just as starting pitches
to slide up into a clean note (like Eb to E), the same way you might
from Db to D in draw 4 on a C harp.
Frankly, you're better off experimenting with this yourself
than paying out huge sums for very little.
As far as the harps themselves are concerned, I had one of the
early ones, with welded reeds, and found that the cover plates tended
to move, got bent by my grip when playing, and was out of tune after
four gigs. Now I'm not one to complain, but ..........
URGENT INFO NEEDED!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
DOES ANYONE OUT THERE KNOW ANYTHING BIOGRAPHY-WISE ABOUT **GARY
PRIMICH**??? I'VE GOT A TAPE TO REVIEW FOR A BLUES MAG. & I KNOW
NOTHING ABOUT HIM - THO' I'VE HEARD THE NAME BEFORE.
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