Re: [Harp-L]Comb test

[Matthew Smart <matthewsmart@xxxxxxxxx>]

I want to make clear that the primary reason I was advocating combs is not tone. Very few can hear it. It is my assertion that most stock combs are not flat and made cheaply.

A perfectly flat sealed after market will bump the performance nearly every time increasing volume and response of the harmonica. If that was not the case I would not have a business.

In regards to harmonicas I love something about every brand and if I had time I would build a custom for myself in most models. I think they all have something to offer

Sent from vermy iPhone

On Oct 28, 2012, at 5:34 PM, MundHarp@xxxxxxx wrote:

> Vern...
> I used to think... Wood comb = warm   metal comb  =  bright...
> Was it in 1997 or 1998 that I was participant with you at SPAH   in 
> Detroit, in the comb test? You know, that proved to me... The audience  can not 
> tell the difference!
> No more, no less!
> John Whiteboy Walden,
> Just now in bonnie Scotland.
> 
> 
> In a message dated 10/28/2012 8:39:32 P.M. GMT Standard Time,  
> jevern@xxxxxxx writes:
> 
> We will  be condemned for using Harp-l bandwidth for this discussion.  
> 
> On  Oct 27, 2012, at 7:08 PM, David Payne wrote:
> 
>> The problem is, Vern,  I believe you're mostly right. But we could do 
> brass vs. wood next time I am  able to get to a Spah where we could do it and 
> I'd like to draw in my other  four most-trusted ears as well, if they'd be 
> willing (Jason Ricci and Wally  Peterman).
> 
> My wager is that nobody can differentiate among comb  materials under 
> controlled coditions. You are welcome to include as many  participants as you 
> choose.  If anyone succeeds, I lose.   Bear  in mind that in in three previous 
> tests, everyone anticipated being able to do  it but no one who actually 
> participated and put their perceptions on paper  could.  Participants included 
> many well-known harmonica virtuosos.   
> 
>> You could give the $1,000 to Young Harmonica Allstars  International or 
> keep it, whatever. I, on the other hand, do not have $1,000  to put up, nor 
> am I really concerned about that money. I only want to better  understand 
> how the harmonica works.
> 
> That also is my goal. I admit that  if I thought anyone could do it, I 
> wouldn't risk $1000. The wager is a way to  dramatize my confidence and the lack 
> of confidence of those who disagree. You  can assemble a syndicate of 
> believers to raise the $1000.
> 
>> I have  thought for years about this and I have been in varying degrees 
> on both sides  of this fence. I was positive that comb material had no effect 
> on tone, Vern  had convinced me of this. I was positive until the 2010 SPAH 
> test. The brass  comb seemed so vibrant to me and I could usually hear it. 
> I was sitting back  far enough where I couldn't see what was what and I made 
> it a point not to  look. What I heard made me rethink everything.
> 
>> I've done  quite a few experiments. Some of those experiments indicate 
> Vern is right.  Some of those experiments indicate that Vern is not. 
>> My current  hypothesis is that we have all been wrong to some degree and 
> that Vern has  been more right than most, but not entirely right.
> 
> I have also done my  own experiments.  However, hearing is very subjective. 
> I have a skeptical  bias and could not trust my own perceptions.  Thus it 
> was necessary to  get other listeners & players involved.
>> 
>> This is  mostly for those following along. I would never insult Vern's 
> intelligence,  which I respect by going into some of these elementary details, 
> and I'm sure  Vern will think I'm full of it anyway, lol.:
> 
> This has nothing to do  with my intelligence or profound lack thereof.  I 
> would have difficulty  defining the word. Consider only my arguments, 
> acoustical theory, and the  evidence from the tests actually conducted.   
>> 
>> The most basic thing that affects tone is the reed itself and the  
> resonant chamber.
> 
> I disagree. The most basic thing is the non-linear  area of the flow 
> passage through the slot as the reed opens and closes  it.  This is very much the 
> same for all reeds. The responsiveness of the  reeds can vary with their 
> stiffness. Two reeds of the same pitch can have  different stiffness and 
> respond differently to the player.  This will be  more apparent to the player than 
> to the listener.  Think Hering and  Hohner.  
> 
>> How it is profiled - the varying thicknesses along  its length...
> This can affect fatigue life, but not tone.   
> 
>> - and how the air flows to the reed. I was fortunate enough to  soak up a 
> lot of Harrison Harmonicas' work on studying the affect of air flow  to the 
> reed on tone.
> 
>> The resonant chamber, of course, is the human  innards.
> I agree. I think of the reeds as substitutes for the human  larynx.
> 
>> Here is an explanation of air flow: 
>> http://www.elkriverharmonicas.com/harp_school/1890s
> 
> I believe that  holes in  the covers an inch or more from the reed have a 
> negligible  effect.  I can place a reedplate to my lips and blow a harmonica 
> tone  without the presence of comb or covers. The air flow pattern must be 
> very  different for draw and blow notes but there is not a perceptible 
> difference in  the sound.  Anyone can play a C and the adjacent B# on a chromatic 
> to  verify this.  Because the pressure ratio is very close to 1, the 
> velocity  of the air is low and the passage is small.  Thus the Reynolds number is  
> small, and the viscosity effects predominate over the inertial effects.   
> That means that the reed doesn't know what the air is doing an inch  away.  
> Holes in the cover may affect what the player hears.
> 
> Most  people think of a difference in tones as they would think of the 
> tonal  properties of materials on instruments such as guitars or mandolins. The  
> problem being that those woods serve as resonant things. Combs don't work 
> that  way. 
> 
> I agree.
>> 
>> Jacob Hohner had a theory back in the  1890s that coverplate resonance 
> had an affect on tone. That was the whole  point of the Mouse Ear Marine Band, 
> to lift the coverplates up from the  reedplate and minimize contact with 
> the reedplate, so the coverplate would be  more free to vibrate. The sound 
> from a guitar, for instance, comes from the  vibrating top, not the "sound 
> hole." the sound hole is actually there to  relieve air pressure inside - even 
> medieval builders understood that. When I  wrote the page linked to above, I 
> thought Richard Seydel's side-vent air flow  concept was more valid than 
> Jacob Hohner's coverplate resonance concept, but  since have changed my mind to 
> believe they are both equally-valid concepts.  Jacob Hohner's vibrating 
> coverplate concept isn't very well accepted, the  argument being how is this 
> possible when your hands are on the coverplate. How  can it vibrate.
> 
> Hohner's countryman, Helmholtz, developed a good  understanding of 
> resonance which is described in his1877 book.  He also  Chapter three describes the 
> operation of soundboards. 
>> 
>> So I did a couple of experiments. First experiment I thought would 
> totally  debunk Jacob Hohner. I tried playing a single note, then laying my index 
> finger across the coverplate. I expected to hear nothing, but I was 
> shocked to  hear a definite change in tone. As my finger was placed on the top 
> coverplate  (as I blew a note), there was a noticeable decrease in treble 
> overtones. So,  my next question was if the finger is on the coverplate, is there 
> still sound  vibration traveling in the coverplate? 
> 
> I conducted essentially the  same experiment.  I concluded that any 
> differences arose from the effect  of the finger on the path from the reeds to the 
> players ear.  Our  perceptions agreed with our biases.  That is why blind 
> comparisons are  necessary.
> 
>>   I sought to answer this on my kitchen  table, which is fairly small. I 
> placed my ear on table and then rapped my  knuckles on the other side and 
> listened to how that sounded. Then, I laid my  body across the table (I'm 6 
> feet two inches tall, 240 pounds). This seemed to  me like a good scale test. 
> I did the same thing while laying across the table  and noticed how the 
> rapping sounded. It was not dampened.
> 
> Assuming that  the cover responds to the excitation of sound in the air, I 
> posit that the  effect is minuscule and imperceptible.
>> 
>> So, I thought,  if the sound can still travel through the material when a 
> weight is pressed  upon it, can it still have an affect on tone - then I 
> realized that you can  only cover less than 50 % of a coverplates' surface. 
> The inside surface is  always uncovered and free.
> 
> In order to have an effect on tone, it must  drastically affect the 
> spectrum of the sound...attenuating certain frequencies  more than others.  Then it 
> must emanate the altered frequencies loud  enough to not be masked 
> (http://en.wikipedia.org/wiki/Masking_threshold) by  the main harmonica sound that 
> comes directly from the slot to your ear without  passing through any part of 
> the harmonica. I posit that this doesn't  happen.
> 
> Vern
> 
>> 
>> 
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