Contrabass Digest

2002-01-15

Date: Mon, 14 Jan 2002 16:25:37 -0800
From: Grant Green
Subject: Re: [CB] Contra Repadding Surgery
 

>I just looked at my Leblanc BBb and my Selmer Eb, and you've got it
>backwards.  The Selmer, which uses floated-in-on-shellac pads, has rounded
>cups, just like a soprano clarinet.  The Leblanc, which has screwed-in flute
>style pads with resonators, has a perfectly flat cup.  I doubt that you would
>be able to use flute-style paper shims to seat the pads if the cups were
>rounded.

What I was thinking was actually comparing the contra clarinet pads
to bass saxophone pads, in terms of amount of surface area available
for the shellac.  What I'm really wondering is whether the contra
clarinet pads shake loose more often.  Since Leblancs have spuds and
Selmers don't, does anyone have comparative data regarding pad
retention?  Not one of my more insightful speculations...

Grant

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Grant Green
Sarrusophones, contrabass reeds, &
other brobdignagian acoustic exotica             http://www.contrabass.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
---------------------------------------------------------

From: "Patrick.Scully"
Subject: Re: [CB] Leblanc Contra Clarinet Design - Pad Fastening
Date: Mon, 14 Jan 2002 22:31:12 -0800

Here is some grossly anecdotal comparative data on pad retention (Leblanc
screw-in pads versus glue-in pads a la Selmer).

I have 3 20+ year old paperclip Leblanc contras.  I have one 1 1/2 year old
Selmer Series III alto saxophone, which I purchased new.   One of the
contras (an EEb) was little used over its lifetime, and has its original
pads, many of which are in reasonable condition, although the springs are
all essentially shot.  On this contra, one of the pads (the RH side B trill
key, absent on the BBb instrument) lost its nut and resonator after about
100 hours of my own playing (and perhaps 300 or so hours from it previous
owner, based on condition of the instrument and case).   This led me to
examine other pads, and I found about 5 seriously loose ones, but these were
easily tightened with a jeweler's screwdriver without removing the keycups
from the instrument.  I applied a drop of my daughter's clear nail polish to
the nuts of these 5 as a "Loctite" adhesive.

My BBb and the other EEb had no pad loss issues, but then, complete
overhauls and repads of these are in process now and were undertaken after
just a few hours play time.  The BBb at the very least will be a good
observational subject, as it has had pads floated on shellac to replace the
OEM pads.

No surprise, all pads on the saxophone are tight, and the saxophone has
received at least 300 hours of playtime.

I don't think we can conclude anything from my own experience, but in
combination with other reports, we may be able to reach a reasonable
consensus on screw-in versus glue-in pad retention.

Retention duration aside, I do find Leblanc's mechanically intricate
screw-in pads to be appealing because the performer can, with a jeweller's
screwdriver, "field float" or tighten a loose pad.  Assuming he hasn't lost
the small nut and resonator, he can even refit a detached pad.  Such repairs
are almost inconcievable in the field with glued-in pads, because the key
needs to be removed from the instrument to perform the initial floatation
(shellac is a powder that is melted in to the upright detached keycup with a
small blowtorch).

Next time you see a Leblanc metal contra clarinet, take a moment to reflect
on the uniqueness and complexity of this instrument -- the 7 to 9 kg of
rigid nickel silver tubing and keywork; the 30-40 keycups EACH with a
threaded receiver (referred to here by some as a "spud"),  one or more paper
adjustment shims, a mulitilayer kid leather pad, a resonator washer, and a
hold down nut.  These are beautiful instruments to behold and to listen to
and are perhaps the most complex wind instruments manufactured today
(excepting one-of-a-kind pipe organs).

The question is why one of the major complications of this instrument -- the
pad fastening technology -- remains on current production models.  Barring a
definitive answer from Leblanc, which may never be officially posted for
proprietary reasons,  Grant has suggested that it may be because the screw
in technology is  best from a pad retention standpoint on such a low pitched
instrument.  I would add that screw-in improves maintainability in the field
and makes the instrument adjustable for wear and flexion at each keypoint (I
think this is why virtually every Leblanc metal contra ever made is still
played!).  Yet, we may discover that neither of these is correct...that
Leblanc chose it for some subtle sonic reasons.  Have we tested the
"altered" Leblancs against OEM screw-in instruments to see if there are
differences in intonation?  Timbre?  Resistance?  Leblanc may be the Sphinx
who has all the answers...

Patrick

***End of Contrabass Digest***

 
Next Digest ->
Previous Digest <-
Index
Top