[Harp-L] More Reed Tuning Questions

[Robert Coble <robertpcoble@xxxxxxxxxxx>]

The question about how far a given reed can be retuned got me to thinking (that's  SCARY, I know!).

Given by Dr. Missin (in Altered States) that there are basically two or three types  of reedplates (long-slot, medium slot, and short-slot), what are the pitch ranges  that are actually used in a given slot? Wouldn't that give some reasonable idea of  the range over which a given reed could be tuned using a specific mensur as the  "default" (i.e., minimal cutting from the original reed blank)?

For example, let's use a "long slot" reedplate. The pitch range in hole 1 blow is  from G3 (the G below middle C - C4) to Db4 (immediately above middle C). (I'm  assuming that "short slot" keys begin with D. If that assumption is incorrect,  just adjust the range accordingly.)

I'm also assuming that all reeds in a particular line of harmonicas (such as the  Marine Band Classic) are cut from stock that is of uniform thickness for all reeds  used in the set of keys from G (lowest) to F# (highest). I'll deliberately leave  out "Low" and "Low Low" harps for the moment. 

For a given reedplate slot, there is a range of pitches required. However, the  length (which is one of the critical factors in determining pitch) is fixed for  that reedplate slot. The lowest pitched reed mensur is cut so that there is a  large "blob" at the free end of the reed. The highest pitched reed mensur is  "shaved" very thin (relatively speaking) throughout the entire length of the reed.

For our hypothetical Marine Band, the required set of notes is G3, Ab3, A3, Bb3,  B3, C4 and Db. That's a range of 6 semitones. Since the notes vary symmetrically  as the pitches increase, it seems reasonable (although entirely based on  supposition) that a given reed BLANK can be tuned 6 semitones (3 semitones in  either direction) without ill effect.

Another assumption is that Hohner (and other manufacturers as well) has spent  innumerable hours studying reed properties, and have determined (either through  trial-and-error or through analysis) that a given reed BLANK thickness will  support a certain range of pitches with a concurrent longevity. Any variance  outside of that range may produce the desired pitch but with (drastically?)  reduced longevity. Again, this is one of those engineering tradeoffs required to  provide an overall optimum pitch, playability and longevity. TANSTAAFL.

I haven't measured the various reed mensurs to determine if this is true. However,  I suspect that for each reedplate slot, there is an optimal pitch, and then there  are suboptimal pitches which can still be obtained with reasonable success.

Now let's speculate about the end points of that range. If the optimal pitch is in  the middle and the end points as an outer limit, then it may NOT be possible to  retune a reed at the end point to a pitch that is 6 semitones outside of that  range AND still retain sufficient longevity to use it. For instance, let's  consider retuning that G3 reed down to Db3. It may be possible to reach that pitch  on the work bench by adding a "blob" of solder on the end of the reed, but will it  have playability or will last sufficiently long under normal playing conditions to  make it worthwhile?  Maybe, maybe not...

This would also account for why certain reeds seem to give out more readily than  others. If the reed mensur is at one of the end points (for instance, D4 in hole 1  blow is at the end point for a "short slot" reedplate), then it seems reasonable  that those reeds would experience fatigue more readily than reeds that were closer  to the "optimal" reed mensur.

And now to refute my own hypothesis: What about the "Low" and "Low Low" reeds? Are  they nothing more than the same old reeds with more weight added to the free end  of the reeds? If so, then it should be possible to retune a reed well over an  octave. Or are the reedplate slots for "Low" and "Low Low" harps considerably  longer (with commensurate changes to the combs), to accommodate longer reeds (with  lower pitches)? Somehow, I got the impression that the reedplates for "normal"  keys are also used for "Low" and "Low Low" harps. (I only have one Low tuned  Bushman, and I'm not in the mood to take it apart, since it is the only Bushman I  own.)

Dang! I'm beginning to understand why Vern strongly recommended against making my  own reeds! I also have a much more profound respect for the manufacturers AND  explorers like Pat Missin, Vern Smith and Smokey Joe McGyver!

I have retuned reeds, but never more than 5 semitones. Like Sam, I don't think my  results have been as good as what comes from the factory. And I am NOT the most  discriminating listener! I decided to do the "smart" thing on my last foray into  repairing harps for other people: I bought the correct reeds from Hohner! The  individual reeds are cheap and it saved a lot of my time; I had 10 harps to repair  in a relatively short time period. (I'm a convert to the Richard Sleigh school of  being "intelligently lazy"!)

And just so we can keep on current topic, I love Paul Butterfield's music! "Better  Days" (it should have been titled "Butter Days") latched on to my heart in a way  that nothing else did when I first started trying to learn to play. I'm not a  blues harp player, but I still get a thrill every time I go back to Butterfield.  Just think of how great he could have been if he had spent most of his time  speculating about reed mensurs!

Merry Christmas to all!
Crazy (enough to dream of my own custom designed harmonica) Bob
  		 	   		  
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