Re: [Harp-L] triple vs quadruple reed harps

[Rick Epping <rickepping@xxxxxxxxx>]

In this experiment, I tuned the draw reed to D above Middle C with the blow
reed blocked.  I then unblocked the blow reed and tuned it to A below
Middle C, and then measured the frequency of the draw reed, D.  I then
started retuning the A reed up in increments as small as 5 cents, each time
re-measuring the frequency of the D reed, which I did not alter.  The blow
reed was incrementally retuned from A below Middle C to F# above Middle C,
each time re-measuring the frequency of the D reed.  The region where the
draw D reed sounded at its highest frequency was where the blow reed was
pitched below it.  On the XB-40, every normal reed is paired with an
auxiliary reed pitched below it.

Best,
Rick

On Sat, Sep 15, 2012 at 7:04 PM, Zombor Kovacs <zrkovacs@xxxxxxxxx> wrote:

> Sorry, I did not quite grasp the concept here:
>
> "In 2003, I conducted an experiment in which I
> incrementally retuned the pitch of an accordion reed over a range of nine
> semitones, measuring its effect on the pitch of the opposing reed in its
> chamber. "
>
> Which was the blowreed and which was the drawreed?
>
> Zombor
>
>
>   ------------------------------
> *From:* Rick Epping <rickepping@xxxxxxxxx>
> *To:* harp-l@xxxxxxxxxx
> *Sent:* Saturday, September 15, 2012 6:20 PM
> *Subject:* Re: [Harp-L] triple vs quadruple reed harps
>
> In regard to Richard's observations, the sole purpose of the XB-40's
> internal valves and valve chambers is to isolate the auxiliary reeds from
> all reeds playing in the opposite airflow direction, with which they might
> otherwise sympathetically play when not wanted.  Indeed, this is the basis
> for my patent, as stated in the following relevant section:
>
> "The use of a single auxiliary reed mounted flush over a slot in a cell for
> bending has been suggested before this invention and no claim is made to
> this invention.  However, such feature is unsatisfactory when multiple
> adjacent cells are used in a harmonica because of undesirable sympathetic
> vibration of reeds in adjacent cells. The use of enabler reed valves
> eliminates this problem and makes possible the improved harmonica of this
> invention."
>
>
> I believe that the unusually high longevity of the XB-40's reeds is
> due partly to
> its comb design, which forces the airflow through the valve slots before it
> reaches the reeds, thereby creating the Venturi effect of both reducing the
> airflow's pressure while increasing its speed.  This reduction of air
> pressure on the reeds should help prevent their being driven past their
> elastic limit.
>
>
> Winslow's point that each normal reed has a responder, or auxiliary reed to
> act as a shock absorber is also valid.  And it's not simply that the
> auxiliary reeds act as shock absorbers.  I tend to believe that playing a
> reed in an environment which allows it to oscillate closest to its natural,
> or plucked frequency, is less likely to stress it than in other, less than
> optimal environments.  In 2003, I conducted an experiment in which I
> incrementally retuned the pitch of an accordion reed over a range of nine
> semitones, measuring its effect on the pitch of the opposing reed in its
> chamber.  I found that the opposing reed tended to play at its highest
> frequency - that is, closest to its natural frequency, when paired with a
> reed tuned lower than itself.  I conducted a similar experiment at this
> time, where I tested the performance of a harmonica's draw reeds when
> mounted with blow reed plates from various keys ranging from lower to
> higher than that of the draw reed plate.  Once again, the draw reeds
> performed best and played at their highest frequency when matched with blow
> reeds tuned lower than themselves.  Better even than when they were matched
> with reeds tuned to the same pitch and better than when the opposing reed
> was isolated from the airstream by a valve.  This phenomenon can also be
> noticed on a standard, un-valved Richter harp, where the draw reeds in
> holes 1 through 6, which are paired with reeds tuned lower than themselves,
> play more easily and require less offset relative to their
> flexibility and pitch than do the draw reeds in holes 7 through 10, which
> are paired with reeds tuned higher.
>
>
> Best regards,
>
> Rick
>
>
> > ------------------------------
> >
> > Message: 3
> > Date: Fri, 14 Sep 2012 22:10:28 -0400
> > From: Richard Sleigh <rharp@xxxxxxxxxx>
> > Subject: [Harp-L] triple vs quadruple reed harps
> > To: harp-l@xxxxxxxxxx
> > Message-ID: <27C9CA42-B0C9-4EB5-A05E-6E65348FAD08@xxxxxxxxxx>
> > Content-Type: text/plain;      charset=us-ascii
> >
> > One of the things that makes the SUB 30 a lot more like a standard
> > diatonic is that the three reeds all share the same chamber. In the XB
> 40,
> > there is a separate chamber with the valves in it that directs the air to
> > additional chambers that each have  two reeds. This results in the extra
> > thickness of the comb. It also creates different internal acoustics, so
> the
> > tone of the harmonica is, to my ears, unique. It has some of the
> qualities
> > of a chromatic & some of the qualities of a diatonic, but also a sound
> all
> > it's own.
> >
> > With the XB 40, your breath takes a more circuitous route before it gets
> > to the reeds. I think one reason why they last longer is the extra
> distance
> > between your breath and the reeds, as well as the constrictions that the
> > air must go through, creates a buffer zone that shields the reeds from
> > extremes of attack. Plus the XB 40 is naturally louder because there is
> > more resonant space to boost the vibrations. Just like the same string
> on a
> > guitar with a big body sounds louder than if it were on a small body
> guitar.
> >
> > With a smaller harp, the tendency is to hit it harder to make it louder,
> > and the reeds are getting a direct hit from your breath.
> >
> > One thing that will take some new techniques and general getting used to
> > on the SUB 30 is this: the way you play it can cause the extra reeds to
> > play sometimes when you don't want them to. Three reeds. one wind-saver,
> > means that part of the time you have two reeds in play and one cut off
> by a
> > wind-saver. The rest of the time you have three reeds exposed to the
> > breath, and one of them rests in the slot to resist the air flow. This
> > third reed can break free and start vibrating under the right conditions
> > (well, really, the wrong conditions - cause you don't want this to
> > happen...) It could be the bending embrochure supporting an overtone or
> > vibration that is close to the pitch the reed is tuned to, causing it to
> > start vibrating.
> >
> > I am learning where this happens, and it is either during a bend with a
> > lot of air pressure, or if I play the wrong chords or double stops. So
> > finessing the air pressure and embrochure is part of the learning curve.
> >
> > I believe that a combination of playing technique and reed set-up will
> > eliminate these problems, but it will take some time to sort out, and
> will
> > be different for different keys.
> >
> > Richard Sleigh
> >
> >
> >
>
>
>