Let me also summarize what I see as the difference between our views on the issue. We both agree that, with “windsavers” - valves placed on the back side of the slot of each reed -, single-reed bends are greatly facilitated, for all of the ten holes in a standard “blues harp” instrument. For me, this fact may, but not necessarily, indicate that single-reed bends are possible in the un-valved instrument, and I’m surprised that others – call them “the Johnston crowd” - claim that the only “normal” bends made with the unvalved instrument are “double-reed bends” – bends that require the presence of two reeds in the same slot, accompanied by the influence of an air resonator (oral/vocal tract). I myself do not claim that these people are wrong, and I’m willing to accept the possibility that they are right. (Johnston’s paper gives strong experimental and theoretical evidence that they are right.)
If I understand your position, you seem to differ from me only that you say that these people are indeed wrong. You simple go further than I do, on this issue.
I must thank you for your document, which is valuable here, and it helps make certain things clear to me. For one, it lays out before us all what the Johnston crowd claim; i.e. that the only “normal” bends you can do on an unvalved blues harp are bends on reeds that have, as accompanying reed, one with lower pitch. Look at your evidence on this point. The only exceptions you show are with holes 5 and 6 on the blow, where the accompanying reed is of higher pitch. You indicate that the bent sound is difficult to hold, because of the parentheses. Thus, would you not agree that your chart gives considerable evidence for their claim?
Okay, I say we are both skeptical, but maybe we just haven’t yet heard enough of the evidence that’s already out there. I read Johnston’s paper many years ago, and I honestly cannot remember how convincing it is. I need to read it again before making any more statement on it.
5) As long as I haven't got such evidence I remain sceptic that there IS any involvment by the "secondary reed" at all and I wonder if there might be some fundamental misunderstanding messing things up
Concerning the evidence you seek, I’ll mention again that the Asian free reed is indeed a reed that necessarily operates as an “opening” reed. If you don’t understand what this term means, I suggest you read Cottingham’s paper, referenced above. As the Johnston crowd explains, the additional reed in the harmonica operates as an opening reed during the bend, in the same way as the Asian reed, and both require coupling to an air resonator. But perhaps the best evidence I can point to at the moment is the Johnston paper. If you (or anyone else) would like me to send you a copy, email me with your address. In the Johnston paper, both experimental and theoretical evidence is presented. With the experiments, they made use of an actual unvalved instrument, powering it through a resonator of variable geometry. I should read the paper again. Being only an amateur, I’m not as familiar with the literature as I could/should be.
Here, I think you go too far, and I think there are physical errors in your understanding. I believe you are in error when you say, “bending primarily involves a changed influence from the airstream and pressure on the singular reed,” if, by “bending” you mean the normal bending – not overblow. With overblow, I agree, a non-uniform air flow (i.e. jets) may be involved. But not so with the normal bend, on the draw. It’s not impossible to form a non-uniform airflow through the reed when you draw. The flow through the reed is then upstream of your mouth, where the vacuum is, causing an air flow approach to the reed is that must be uniform. I’m not sure what happens when you do a normal bend on an unvalved harp with a blow – one reason being because I never learned how to do it. But with a valved harp, the blow bend is produced also by a uniform flow, without the “whistling” you explain for overblows.
6) As far as I can understand bending primarily involves a changed influence from the air stream and pressure on the singular reed.
The vocal tract - when acting as a resonator in these cases - only adds tonally to the sound produced by the "primary reed". The assumed involvement by the "secondary reed" I still this far regard as a theoretical construction without practical evidence. There is a considerable tonal difference between bending simply by using overblow or overdraw technique with very tight lips ( as if you just whistle into the harmonica) or a technique opening up the mouth ( "swallowing the tongue method") but I don't yet understand or accept that the later means any involvement (="coupling") of the "secondary" reed.If one looks at the theoretical combination patterns between the "primary" and "secondary" reeds in the same chamber there is no sensible pattern in the note results.How are for example the options explained to do continuous pitch transitions from D-C#-C or B-Bb-A-Ab while the "secondary reed" is completely inactivated??
I strongly disagree. As I noted above, the patterns I see between the primary and secondary reeds give strong evidence for the Johston crowd. One last point I can make is by asking, since you are aware of overblowing (whistling) techniques, isn’t it true that, when you overblow, you also force the reed to speak with an airflow that is in opposite direction to the ordinary? I’m not 100% sure, but I’m pretty sure that, with overblow, the main speaking reed is again operating as an opening reed.
If one looks at the theoretical combination patterns between the "primary" and "secondary" reeds in the same chamber there is no sensible pattern in the note results.
I didn’t know that such large bend excursions were possible with the unvalved harp. If it’s true, then I don’t know the answer to your question.
How are for example the options explained to do continuous pitch transitions from D-C#-C or B-Bb-A-Ab while the "secondary reed" is completely inactivated??
I think at this point, we really need someone with more knowledge to chime in.