[Harp-L] Re: Altered reed shapes

[Rick Epping <rickepping@xxxxxxxxx>]

I'm sure there are sites dedicated to accordions- didn't Winslow mention an
accordion forum?  Concertina.net has some good concertina related
information.

A reed block is the part of an accordion that's like a harmonica: a wooden
battery or comb onto which the reed plates are attached.  A reed block is
mounted onto the inside of either the treble or bass foundation plate.  The
key pallets (valves, or Klappen (German)) rest on the opposite, outside of
the foundation plates and are raised by the accordion's keys or buttons,
allowing air to pass through the reeds, either into or out of the accordion.
The foundation plates are part of the bass and treble cabinets, which are
the housings on either side of the bellows which contain the reed blocks and
key mechanisms.

Cassotto, or tone chamber accordions have one or more sets of reeds for
which the reed block is not set onto a foundation plate but onto a box about
the same size as the reed block, with one internal chamber shared by all the
reeds.  This tone chamber is set onto the inside of the foundation plate,
which has one large opening to the outside, into which the pallets are set.
 If a reed block is the equivalent of a harmonica, a tone chamber is the
equivalent of the harmonica player's cupped hands.  Tone chamber accordions
are relatively expensive, partly because of the extra parts needed, but
mostly because it is very labor-intensive to adjust the key mechanisms of
tone chamber accordions.

"Reed shoe" is a term used to describe the individual reed plates in
English-made concertinas.  They're called reed shoes because they are
somewhat shoe-shaped, tapered so that they can be wedged into the wooden
reed pans (the concertina's equivalent of a reed block).  One interesting
thing about English-made concertinas is that their reeds, at least the steel
reeds, rarely wear out.  Something to do with their design I would guess.  I
did blow a reed in my Crabb concertina during a recent tour of Denmark and
Shetland, the first reed to go in that concertina since I bought it new in
1970.  I've uploaded a couple of photos of the new reed I cut for it.  One
photo shows it under construction and the other shows it fitted to its reed
shoe.  Here's the link:
https://docs.google.com/document/pub?id=1nprVdLeSOPlq3J7qECgDDrR7xld9KNz60SOBW6m4BiM

Best,
Rick


> Message: 5
> Date: Wed, 11 Aug 2010 23:20:15 -0600
> From: "Doug H" <dough.harpl@xxxxxxxxx>
> Subject: [Harp-L] Re: Altered reed shapes
> To: <Harp-L@xxxxxxxxxx>
> Message-ID: <AF09DCEC1E974857ABB37F1E2E80C160@velocity007>
> Content-Type: text/plain;       charset="UTF-8"
>
> Great information Rick!
>
> However, there are a few terms relating to accordians that I don't
> understand.  For example "cassotto",  "cassotto tone chamber",  "reed shoe",
>  "reed block" and "cabinet".
>
> Is there a spot on the web that would clairfy these terms, and maybe teach
> me a bit about accordians in general?  Thanks in advance for any info.
>
> Doug H
>  ----- Original Message -----
>  From: Rick Epping
>  To: harp-l@xxxxxxxxxx
>  Sent: Wednesday, August 11, 2010 1:24 PM
>  Subject: [Harp-L] Re: Altered reed shapes
>
>
>  >
>  >
>  > The spectrographs of all the harmonica reeds I studied while conducting
>  research for Hohner showed what appears to be a low signal to noise ratio;
>  that is, the amplitude of the dissonant overtones was very low compared to
>  that of the consonant overtones.  The amplitude of the dissonant overtones
>  only increased significantly when the harmonica reed was blown loud enough
>  to start distorting.  I believe that what makes harmonica reeds sound thin
>  and reedy is the relatively high amplitude of the upper partials, or
>  consonant overtones, and not so much that of the dissonant overtones.
>
>
>
>  Some aspects of reed design that can influence the strength of the upper
>  partials compared to the 1st partial, or fundamental tone, are: 1. Reed
>  thickness (especially the thickness of the reed at its edge) - a thin reed
>  will have stronger upper partials than a thick reed.  2. Reed dimensions -
> a
>  narrow reed will have stronger upper partials than a wide reed.  3. Reed
>  plate thickness - a thin reed plate will produce stronger upper partials
>  than a thick reed plate.  English-made concertina reed shoes are undercut
> to
>  create the effect of a thin reed plate, giving these instruments their
>  characteristic reedy tone.
>
>
>
>  I believe that what is at least as influential as the reed to the tone of
> an
>  instrument is that of the instrument design and construction.  For
> example,
>  clarinet accordion reeds in cassotto are identical to those in the same
>  instrument that are not in cassotto, yet the tone of cassotto reeds is
>  significantly warmer and rounder than those not in cassotto.  This is
>  because the cassotto tone chamber shifts energy from the upper partials to
>  the fundamental, making the fundamental actually louder than that of the
>  same reed not in cassotto.  While playing a harmonica note into a
> microphone
>  to produce spectrograph, I found that going from an uncupped note to a
>  cupped note caused the amplitude of the upper partials to decrease and
> that
>  of the fundamental partial to increase, just like an accordion's tone
>  chamber.  Similarly, the reeds of an XB-40 are identical to those of a
>  chromatic yet, due mainly to the XB-40's internal valve chamber, the XB-40
>  produces more of the fundamental tone and less of the upper partials than
> a
>  chromatic, giving it a warmer, rounder and loud, but less bright tone.
>
>
>
>  Italian accordions might be characterized as having a warm, pure and round
>  tone compared to German accordions, which tend to be more bright.  Here
> are
>  some possible reasons: 1. Italian reeds tend to be thicker and stiffer
> than
>  German reeds (this need not affect response, as stiff reeds can be given
>  less offset than more flexible reeds).  2. Italian cabinets are generally
>  thicker and heavier than German cabinets, and can absorb more of the upper
>  partials.  Likewise, Italian reed blocks may be heavier than German reed
>  blocks, having the same effect.  3. Italian accordions more often use
>  leather reed valves and German accordions usually use PVC reed valves.
>  The
>  heavier, softer, rough-surfaced leather valves absorb more upper partials
>  than the thin, reflective PVC valves.  Lastly, 2-voice tremolo tuning on
>  German accordions is usually faster than the standard 2-voice, Violin
> tuning
>  common to Italian accordions.  This also helps to give German accordions a
>  brighter tone compared to the more pure tone of Italian accordions.
>
>
>
>  Some harmonicas can be overly bright, especially harmonicas that have been
>  customized for maximum performance.  But in general, most players might
>  prefer a somewhat bright instrument, where there is a greater possible
> range
>  of tonality by means of hand cupping.  A bright harmonica can be made
> warmer
>  and more fundamental in tone by means of cupping, but less can be done
> while
>  playing to make a harmonica with a predominantly mid-range tone more
> bright
>  sounding.
>
>
>
>  Rick
>
>
>
>