[Harp-L] The comb materials debate



Seems to be two fundamental questions in this debate:

1. Does comb material affect tone?
2. If so, can the affect be heard by humans?

I'm not familiar with the previous comb tests done at SPAH, but the discussion has me wondering if there have been any tests using completely off-the-wall comb materials like styrofoam, rubber, paper, cardboard, or "Great Stuff" foam? How about combs surfaced with a layer of felt inside the reed chamber? If a radical departure to materials that seem, on the face of it, to be completely inappropriate for harmonica combs demonstrates an audible affect on tone, then THAT question would be settled and the discussion could move on to just how much affect the various "normal" materials have rather than an argument about whether there's any at all. I would expect a styrofoam comb to sound like crap, but does it?

I believe (but don't KNOW) that the comb material does indeed affect the sound that emanates from the harmonica as a whole (not just the reed), but I'm not convinced that humans can discern the differences reliably if at all because it hasn't been demonstrated convincingly. Sound waves are reflected by various materials in different ways, and different materials have more or less affect on those reflections at different frequencies. The sound waves generated by the reed will collide with the comb material, and the material will either absorb or reflect the sound energy to varying degrees depending on the frequency, in accordance with it's relative density and the nature of the material's surface finishing (porous, smooth, hard, soft). Thus the same material might affect the reed on hole 10 to a different degree than it does on hole 1 because of the different frequencies involved. Is the chamber too small to have a significant affect? That's more than I can figure out.

Same things would apply to cover plate materials: Anyone ever try lining them with felt? I would expect that a felt lined cover plate or a styrofoam comb would sound like crap.

I also wonder about the reed plate's affect. Once mounted, isn't the plate effectively coupled with the comb, and might its ability to transmit vibrations from the reed to the comb material (thus using up energy from the reed) also vary with frequency. Has anyone tried mounting reeds directly to the comb material? A reed plate on a steel comb would seem superfluous unless the plate itself has some affect on tone (or just makes the harp easier to manufacture). But would a reed mounted directly to wood create a different tone than one on a brass reed plate?

Somebody on this list may have already mentioned that in blind listening tests humans are likely to interpret a small change in volume as an improvement in sound quality. We are very easily fooled.

I doubt the argument will ever die no matter what testing demonstrates. There are folks who pay thousands of dollars for 15ft speaker cables because the maker tells them they can carry frequencies that their dogs can't even hear. I'm certain that almost everyone in any audience doesn't know or care what a harmonica's made of and cant' tell the difference, just like they can't tell by listening if you use JBL or EAW speakers in your PA, or whether they're line arrays or boxes. They also don't know or care what kind of microphone you're using, or whether you have a vintage amp or a modeler; that stuff is all about how the player feels, which of course affects performance. As long as they hear reasonably good sound quality and the melody, all that matters to an audience is the music and the quality of the performance. I say, if it feels good to play it, it's workin' some kind of magic so go with it. Not every mystery needs an answer.

Harry



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