Re: Subject: Re: [Harp-L] comb material

It seems I have stirred up still water (if there is
any saying similar to this in english) with the comb
material topic :-)

I have a music box right on my table. Although it is
mounted in a plastic box, it still works. My desk is a
solid wooden desk. 
The followings have been revealed. I have placed the
music box onto the following surfaces:

My palm
Solid wooden desk
My room door (must be hollow inside)
My room window (double glass with air in between)
My room wall covered with wallpaper
A thin wooden box cover (size about 20 x 15 x 0,3 cm)
A blanket


My palm is the reference loudness
Solid wooden desk - lets say twice as loud
My room door - 3 times louder
My room window - slightly more quiet
My room wall - more quiet than my desk
Thin wooden box cover - louder than my door
A blanket - more quiet than my palm or hands

Conclusion: the music box reeds conduct vibration to
the whole music box body. If you hold it in your
hands, it absorbs vibration energy a great deal. A
blanket absorbs vibration energy even better, it even
absorbs sound. The music box is a vibrating item. If
the surface onto which it is placed conducts
vibrations well, and is free to vibrate, also it
rather reflects sound than absorbs it, it will
"amplify" sound. To put it in other words, it does not
absorb the energy rather than amplifying it. 

I tried the same with a reedplate. Nothing comparably
significant could be achieved. I plucked the reeds. It
sounded louder when I held it against my desk. Or it
didnt. Or did it? I dont know. No significant
difference for sure. Why is there such a difference
with the music box then? I think music box reeds store
more energy. THose reeds are made of steel and are
thicker. They may be narrower, but they require much
more force to bend (have a bigger bending moment).
Harp reeds have such a low bending moment. No
significant "amplification" can be achieved. I have
also tried to compare plastic and metal combed harps
again. I am absolutely not sure, if there is a
difference. There may, or may not be a difference. The
conclusion is, it is not significant. 

A main difference between the music box reeds and the
harp reeds is that one is plucked the otherone is
vibrated by an airstream. The harmonica reed vibration
is a much much more complex phenomenon whith a lot of
aerodynamics. So I also think, that although the
strings on a guitar vibrate in a similar manner as
reeds do in a harmonica, the scales are different. A
harmonica comb is so ridgid and contains so little air
volume, that it cannot significantly contribute to a
change in tone. On the guitar, the strings conduct
vibration into the whole guitar body, which then
"amplifies" the sound. Probably if harp reeds were
made a 100 times more stiff, then creating a large,
hollow harmonica comb would then make a difference. 

Reed stiffness in a harp is so low, and vibration
energy is so little, that there is not much to conduct
away by the comb. If there is still something,
probably Vern's theory has something to do with
personal biases, but I doubt that lips are good
conductors of vibrations.


--- Rick Dempster <rick.dempster@xxxxxxxxxxx> wrote:

> Zombor;
>               Re. "The tuning fork issue". OK. But
> what about  (seeing
> as you appear to be referring to my post) the "music
> box issue"? The
> tines of a music box are smaller than the reeds of a
> harmonica. But when
> you place the tiny, tinkling, barely audible music
> box movement onto a
> solid wooden surface, bingo! it becomes loud (that
> is why the thing is
> always screwed into a wooden box)
>              A harmonica, or a harmonica plate does
> not behave like
> this.
>              I do not quite know how the music box
> tines differ from
> the harmonica reeds, but I suspect it is because
> they are not
> independently mounted, but are part of a 'parent'
> material, the various
> reeds all being part of the same piece of metal;
> something like the
> tuned zones on a Carribean steel pan.
>             If you are reading this Vern, I wonder
> if you might be able
> to add something to this speculation.
> RD
> >>> Zombor Kovacs <zrkovacs@xxxxxxxxx> 18/04/2007
> 17:21:25 >>>
> > incentive for me to participate.  I find it
> vaguely
> > embarrassing  (and not a bit 
> > insulting, actually), 
> Don't be too sensitive. If you have a very acute
> hearing, it only means that you probably notice
> slight
> differences, what others dont. This would only
> confirm
> the fact (?) that different comb materials do not
> turn
> the world around. I guess Vern is not speaking about
> nothing, and his statements are based on tests. The
> problem is that mine are too. But the purpose of my
> tests were not to check the differences between comb
> materials, it was just a "side effect". I just know
> that there is a big difference in sound between the
> first harp on my webpage ( which
> has
> the same Hering reedplates as the original with
> plastic comb. The second harp also has the same
> "metallic" sound. The plastic combed ones have a
> much
> softer sound. The audience might not be able to tell
> the difference just like that (it was not me who
> made
> this statement), but the player will definitely feel
> it. The Hering Vintage Harp has however a wooden
> comb,
> but still has a similar "metallic" sound. So even
> myself am not sure, but putting the same reedplates
> on
> a metal comb makes the harp sound significantly
> different, at least for the player.
> The tuning fork issue. The tuning fork has
> hundredfolds more mass than a reed, thus if you push
> a
> vibrating fork against a table, it will "shake" the
> table which would amplify sound. The same will
> happen
> with a reed, but the mass is so much smaller. I
> don't
> know if the amplification is percievable. It
> probably
> is, at least in the overtone range. 
> My question now is: what does then effect the sound
> of
> the harmonica? 
> Reed material? People say it doesnt.
> Reedplate material? No.
> Comb material? No.
> Coverplate material? No.
> Something must, because different harmonicas have a
> different sound. According to what you are telling
> me,
> no material effects the sound of the harp. This
> would
> mean, that the harp could be made of plastic, it
> doesn't matter. What does matter then?
> Zombor
> I believe that Vern is not speaking about nothing.
> He
> is just saying that there is no significant
> difference. Like changing the comb material will not
> turn the world around. I have plastic combed harps,
> metal combed harps and wooden combed harps. But now
> I
> will make a harp comb made of soft sponge, just to
> try
> an extremity. I 
> >  A real, objective scientific study would surely
> > resolve  the issue for once 
> > and for all, wouldn't it?  Until then,  it's quite
> > likely that folks are 
> > simply tired of being harangued if  they express a
> > contrary opinion, since at this 
> > point it still is only  your opinion, isn't it,
> > without real scientific back  
> > up?   
> >  
> > Elizabeth
> > 
> > 
> > 
> > 
> > 
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