[Harp-L] Re: Rick Epping: the Father of Embossing

[Rick Epping <rickepping@xxxxxxxxx>]

Hi Vern, David, Joe,

Vern, in answer to your questions,

Q. What were the clearances in fractions of an inch or mm that the player's
found to be excessive?
A. I haven't found any limit in clearance reduction that diminishes the
positive effects of embossing.  But I think most will agree that the closer
the embossing, the more the higher frequencies will be strengthened. There
comes a point when some listeners may find the instrument excessively
bright, so it's a matter of taste.

Q. What is the optimum clearance?  Is it different for different reed
lengths?
A. I would say there's no optimum clearance - it's a compromise between
excessive brightness and improved performance, to be determined by
personal preference.  The tightest clearance I might work toward in
producing a harp biased toward performance would be about 0.01mm at the
free end and middle of the reed, reducing to 0.00mm at the rivet end.  The
zero clearance at the rivet end can be extended further along the shortest,
high pitched reeds because they are thicker there than the long reeds and
undergo very little movement where they are thick.

Q. What is the best way to measure clearance?
You might have some suggestions here!  I guess most embossers just learn to
eyeball (with magnifying lenses) the amount of clearance that works best
for them.
A. I studied reeds under the Hohner factory's CNC measuring microscope
during the time we were working on specifications for new reedplate tooling
and got something of a feel for the absolute values involved, but I can't
say that it's all that necessary for good embossing.  I was also able to
make rough measurements of clearance by measuring the projection of
reedplates on the microfiche reader I had in my office.

Q. Is it more important in diatonics than in chromatics where valves block
leakage through the opening reed?
A. All harmonicas, valved and unvalved, can benefit from embossing.  Most
of the session harps I play for Irish and Old-Time music are valved octave
harps, and I emboss them all.

Q. What is "compression" and how is it measured?  Is it the opposite of
leakage?
A. Correct - compression, as I understand it, is the opposite of leakage.
 But how best to measure it quantitatively?  The greater the compression,
the less the breath pressure needed to make the reed play.

"I enjoyed reading the history of Epping's use of embossing to reduce reed
clearance.

However, it is a process and not a result.  His article leaves the
quantitative questions unanswered.

Q. What were the clearances in fractions of an inch or mm that the player's
found to be excessive?
Q. What is the optimum clearance?  Is it different for different reed
lengths?
Q. What is the best way to measure clearance?
Q. Is it more important in diatonics than in chromatics where valves block
leakage through the opening reed?
Q. What is "compression" and how is it measured?  Is it the opposite of
leakage?"
Vern

---------------------------------

Hi David,

Have you done any research on the history of reed chamfering?  I learned of
it from Sissi Nitsch, who said it was a technique that some old-timers used
to practice.  Its effects are similar to those of embossing: improved
response, increased loudness and brighter tone.  It's also a much easier
procedure than embossing.

For those unfamiliar with the technique, I've posted photos and description
here:
https://docs.google.com/document/d/1hHeMSL1Pt3MV2U9HWGoPBCYicfukRP6W09CpfVssinU/edit

"Leo Diamond has an embossed tone. I have heard that tone nowhere else and
from nobody else before recent memory.
Now, people have been customizing harmonicas as long as there have been
harmonicas, that's something I do say often. Most of the earlier work was
done to the reeds or the combs, or slide assemblies, etc. to solve specific
problems."
David

--------------------------------

Hi Joe,

There are a couple of good reasons why it's unlikely that embossing has
been done on accordions.  First of all, since the early 1930's accordion
reedplates have been made of duralumin and have a much higher tensile
strength than do harmonica reedplates.  I've tried to emboss them and have
found it nearly impossible.  The pressure needed to raise any kind of burr
was so great that I feared any slip might damage the reed.

Accordion reedplates would certainly not have been embossed at the factory,
since the technique is so time consuming.  Reedplate coining achieves
similar results and can be done rapidly by machine.

It's also unlikely that embossing would have been attempted by professional
players on their accordions as an aftermarket procedure even if it were
possible to work duralumin plates, for the simple reason that the
instruments are just too expensive to mess with.  The cheapest accordion in
Hohner's top-of-the-line series is the Gola 414.  It's current retail price
is in excess of $49,000.

In 40 years of working on accordions I have never seen one with embossed
reed slots.

"How do we know that embossing wasn't being done on accordions? As you say,
solutions sometimes come from a necessity. Tone a little weak on the D draw
of the pair of reeds in block #10 on bank #3? The chord doesn't sound
'full' on the lower tremelo?  Let's emboss it. Makes me wonder.
Po-see-bee-lay? Hmmm, maybe.
smokey-joe"


Best regards to all,
Rick