Supercorder: Some Tips and Principles:
Some Recorder design notes for aspiring makers, general and Supercorder
by Craig Carmichael
I always like to pass on my findings/knowledge/experience to those
who'd like to improve things. In answering you, it occurs to me I
should put this rather poorly known general info up on the Supercorder
page for posterity, and at the same time, I've put in more info than I
would otherwise would just writing to one person, feeling it's probably
more than you were asking for.
I am considering making some innovations on me and my
friends recorders, and wanted to ask where you got information
about, well everything?
Well, here and there. It's too long ago to remember specific web sites.
You'll have to search and read up on various topics yourself: voicing,
tuning, general principles, and so on. But here's a few pointers, info
that may be harder to come by...
My shortened beaks with the tuning hole covered by the lower lip still
(AFAIK) make them the only duct flute you can tune by ear as you play,
hardly thinking about it, making it fit in in "any old" ensemble where
they won't understand if you can't, eg, do a fade ending or play
pianissimo in tune. I don't think hardly anybody appreciates what a
real difference that makes.
One might (?) lengthen the beaks and windway, and then make the lip
tuning hole larger diameter. I haven't tried it. But in order for the
lip to cover the hole nicely, the shape against the lips needs to be
something like I made it, not the traditional/familiar arc -- that
really has no particular musical/playing purpose.
My wider windway (16-18mm or so) that follows the inner bore with no
undercutting makes for more volume especially in the lower register,
where the strong tone is really like no other instrument. This is also
helped by the large diameter surround "shading" the sides of the labium
in a sense. In the second octave the sound becomes more typically
'recorder'. In the third octave it gets somewhat hissy unless you suck
the moisture out just before blowing the note. Since the exact sonic
character depends somewhat on the "waves" of the moisture lining the
windway, different windway materials with different textures and maybe
porosity can provide different characteristic sounds especially in
upper registers. (Eg: With plastic recorders the upper notes often
hardly sound at all the first time, then sound great on the second try
once the moisture has been blown out. Frustrating!)
A narrower windway/labium might improve the upper octaves, but would
probably reduce the power of the lower one, which needs the most power
to be heard in an ensemble. (Worth experimenting with?)
The longer bore with a tone hole in the right place for each semitone
and keys where needed gives more power and resonance and more even
volume on all the notes including the low ones. (Most altos are made
acoustically too short for the lower notes in order that the bottom
finger holes are reachable.)
I originally followed the bore of the Paetzold/Mollenahuer "Modern
Alto" which has very nice lowest notes. But since I didn't undercut the
windway, that modified the bore profile... and all for the better, it
seems to me. The note holes all had to be changed, moved down the shaft
a bit. But my thumbhole is (IIRC) in the same place, so it's farther up
from the index finger hole. Some highest note fingerings changed, but
then it has keys too, so it's a bit of relearning anyway.
The holes must be both in the right place and the right size to be in
tune in both octaves. In the lower octave the tuning is most affected
by the distance/position down from the labium, and in the upper it's
more affected by the size of the hole. And this all depends firstly on
the inner bore profile, and the hole size depends also on the thickness
of the wall between the bore and the outside, the "chimney height".
There's more on metalworking for doing keys in a jewelery making book
than a metalworking book. "Nickel-silver" AKA "German silver" AKA
"nickel-brass" (Cu:Zn:Ni eg 65:18:17%) is the metal you want for keys.
Web search to find sources. (The one I used most was metaliferous.com)
Brass is okay too but a bit softer and best lacquered or plated. Pure
actual silver (Ag) or sterling silver is much too soft. Piano wire, eg
.030", is good for inner shafts. I made my cups from sheet metal and
the levers from 5/32" nickel-brass rod. The rod I flattened and bent as
required (I eventually made a jig to clamp them and got a jeweler's
rolling mill to flatten them evenly, and for the cups I made punches
and dies from carriage bolts and drilled-out nuts. In forming the wire
it may be necessary to anneal it to keep it workable, either before or
during bending/flattening. A hammer & anvil also works okay for
flattening if you don't want to bother finding a rolling mill.
The B/B-flat key was an original idea that inspired me to make the
supercorders in the first place: lightly cover the open tone hole for
B, and press it down to cover both tone holes for B-flat and notes
below. The low A-flat hole and key gives strong sound on both low
A-flat and A, and as long as it needed a key mechanism, I made the
longer bore and low E key as well to extend the range a bit. (It also
replaces functions of a "bell key" that might have been added.) The
E-flat and D-flat keys were inpired by clarinet E-flat/(B-flat in upper
register), but I put two rings on the middle two right hand fingers to
activate them instead of just a triple one on any of three fingers.
The porcelain beaks are very nice but owing to the difficulties with
dimensions as the clay dries and then is fired, and the hardness of
fired porcelain, I expect ceramic (bisque fired clay) would be much
easier to work with. It took me a long time to get good voicings, in
fact I didn't really accomplish it until well after I had quit making
them, and the hardness of the porcelain was a definite contributing
factor. The one I play now sounds fabulous... after 3 or 4 years, once
I had "tweaked" the windway a couple of times and sharpened the labium.
Ceramic would be easier to sand and grind smooth and flat. You won't
get good voicing without hiss unless the windway is even with good
bevels and aimed correctly lined up with the labium, the edge of which
should be quite sharp.
But I figured all along that if I had met someone who had some
experience voicing recorders who would help, the problems would have
been quickly solved, instead of dragging on for years and after
everything else was history. These days, the first place to check would
probably be youtube.
Denser, heavier woods give more resonance - not a myth or just, um,
'snobbery'(?). Some woods "fur up" gradually or quickly with breath
moisture, and maple expands unevenly, becoming an oval that doesn't
play well. My favorites are pau ferro (Brazil) and African Blackwood.
Other smooth, hard rosewoods are probably great too. Indian rosewood I
used was rather coarse grained. (I only made a couple of dozen
instruments altogether.) With the porcelain mouthpiece, allergy to
rosewood may be less of an issue. An ebony recorder I made kept
cracking and was nothing by trouble. Great for violins that stay dry,
but I'd never use ebony again for a wind instrument.
Hope that helps,