[Harp-L] Combs!

[Jonathan Ross <jross38@xxxxxxxxxxx>]

The following quotes are Richard Sleigh:

"If you don't think comb material makes a difference in the sound of  
a harmonica, I have a couple of experiments for you to try out:

Take a 1/4" thick piece of foam core board and make a comb out of it.  
Add reed plates & covers and play. Can you hear a difference now? How  
about rubber?"

One problem, you know that there is a different material.  Knowing  
this, you will more likely than not hear a difference--whether or not  
one actually exists.  This is the psychological effect of knowledge  
and expectation.  To truly create an experiment, you would need to  
eliminate that knowledge.


"Some materials reflect sound, some absorb it."


True, but you need a sufficiently large surface area to have either  
effect.  The harmonica comb just doesn't give such a surface area.


" An unsealed pearwood comb absorbs some frequencies that a sealed  
pearwood comb reflects and amplifies. That is my experience, what my  
ears tell me. I also hear differences between brass, aluminum, and  
other materials. Sure, you could mess me up if I had to listen to  
someone else play the harps while I was bilndfolded, but there is a  
difference between how I play and what I hear through bone  
conduction, etc."


Bone conduction has been discussed here several times.  The basic  
point was that any possible effect from such would be completely  
overwhelmed by the massive column of vibrating air moving in your  
throat as you play, not to mention the one right around your head.


"If we really want to settle this once and for all, there are devices  
that can measure sound and quantify it much better than most humans.  
That would be much more scientific."


It would be, although listener or even performer based tests are  
useful as well.  The issue may be more nuanced than simply on/off  
(effect, no effect).  It may be that there is a subtle effect, but  
(as Vern has said) if it is outside of the range of human hearing  
then it could be dismissed as insignificant.  I'd love to see more  
tests done and some actual research, but there hasn't been any  
significant movement since the two listener-based tests, at least not  
reported to this list.  So for now the combination of no good theory  
as to why comb material would make a difference (verses a very long  
set of reasons why it wouldn't) and the only tests done indicate that  
there is no difference.


"I was not at the comb trials that have been referenced, but at best  
they were empirical science. Not definitive proof. If someone  
recorded samples and produced voiceprints or some other spectrum  
anaylisis visuals; and they came up identical for different  
materials, I would be willing to believe that my ears are fooling me  
when I hear differences in comb material."

They are the best we have so far.  But there can be no proof that  
comb materials don't make a difference--only an absence of proof that  
they do.  If all tests show no difference, then the logical  
conclusion is that there is none.


These quotes are from Bradley Harrison:

"I agree with Steve Baker totally! There are differences in comb  
material, sound and feel in ones mouth! I am one to always ask  
questions and find answers. I am lucky to have access to high tech  
measuring devices to find these answers, and have performed  tests on  
different materials. It is interesting the different sound waves that  
I get from different comb materials."


Please share these tests with us.  I'd be interested in how the tests  
were undertaken, the controls used, the samples created and the  
results.  The keys for me would be eliminating variables between  
samples and ensuring a blind player (or no player at all).




 ()()    JR "Bulldogge" Ross
()  ()
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