[Harp-L] comb materials



Jonathan Compton writes:


"Why is the burden of proof on the "material matters" people?  Why is the prevailing position that the material doesn't matter until someone proves otherwise?  Why isn't it that the material *does* matter until someone demonstrates that it doesn't? "


As Vern said, the burden of proof is on those who believe in a difference to show that it exists--if I believe that the size of the reed makes a difference in tone, for instance, then to be taken seriously I need to have at least a plausible reason for this belief (a hypothesis of what physical actions would make such a difference real) and then to try and prove that belief by controlled tests.  Which leads to the later two questions of yours: there have been two attempts to test whether or not comb material effects the tone, sound, whatever of the harmonica.  These may not have been perfect tests by any means (see the archives) but they were attempts.  Both came out clearly that people in the tests could not hear a difference in tone.  Thus, those who still want to beleive that material makes a difference to tone have (for the most part) moved away from the previous assumption that the listener can tell to claiming that the player can tell (see below)--the idea that listeners can 
tell the difference has mostly been abandoned since those tests.  That's the history of the debate on this list and speaks to the questions you ask.


" Perhaps an experienced player could record playing a set series of notes/techniques with a wood comb, then repeating the same with a plastic (or other) comb.  If the sounds are identical (or can even be made to sound identical) as determined by human ears, sound analyzing equipment, or some other measurement, then there may not be a difference (at least within the limits of whatever is used to judge them).  Record the passage a few times w/ each comb and completely randomize which clips are played.  (Okay, so the player might be able to compensate for the difference entirely through ability, or might subconsciously play differently...I admit, it's not a perfect plan, but apparently, neither are the previous attempts to approach this from the neighbor's pasture.)"


It's very similar to what's been done, twice, and the resutls there were that people could not hear the difference in the tests.  


"So until someone does that, I'm going to stake my position on the side that *feels* that "comb material" matters (although I admit, I really don't *think* it does)."


Someone has done that.  In fact, two people have done it twice.  Again, see the archives for more information on this.  Feel free to believe whatever you want, but if you want to argue for a position you need to have a theory of why material makes a difference and that theory needs to fit the data so far collected.  That said, I'd love it if more people want to try and do more tests on the subject of comb, cover or other materials.  Whatever the data that results, it will be for the best.


Joe Spiers wrtites:


" Maybe some frequencies that your eardrums can't transmit can make it through this path, or maybe it just "fattens up" some that you normally do. Maybe the different combs do a better job of transferring vibration to the skull and it resonates too. Just ideas here, maybe it's been hashed out before."

This one has also been hashed out before in the archives, check under "bone conduction" for one.  The problem is simple, and I think Vern was being generous when he said that the comb does vibrate enough to transfer sound--the comb is essentially inert, it is clamped in place very securely.  It doesn't vibrate freely in any way shape or form.  It is inert.  

Try the plucking thing in the following way.  Place the end of the comb on a table.  Now pluck the reed as you did.  Not the reed-plate as you did, but the reed-plate and comb combo.  To be sure you aren't hearing anything from the opposite set of reeds, tape them off.  I doubt you will hear a difference in volume, and thus no vibrations coming through the comb.  This, of course, is not a scientific test, but it is indicative of how dead the comb is.  For a scientific test, you'd need to eliminate variables other than the comb, to make sure the listener didn't know what comb material was being used and so forth.

"To say that "if the listener can't hear it, it doesn't matter" isn't entirely true, because if the instrument is offering something that inspires the player, the listener can also benefit. IMO. "


Yes, which is why the psychological effect of materials is so important.  If I like the way the instrument feels, that is going to impact my enjoyment of playing the instrument.  Theoretically, if the instrument sounds differently to the player that would also have an effect.  However, that is both very hard to test (how do you make it so the listener doesn't know what material he is playing) and so far the past debates on "bone conduction" and the like tend to point out flaws in the theory--the primary being that the gigantic column of vibrating air when you play would mask out, drown out or otherwise make un-noticeable any information which could be transfered in this way.  Thus, when you plug your ears you aren't hearing conduction from the instrument itself, but rather you hear the column of air which is moving through your lungs, throat and mouth.  However, it's an area which could be interesting to try testing.

JR "Bulldogge" Ross
& Snuffy, too:)



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