I've seen youtubes on tuning your harp and understand that as you naturally breathe through the harp moisture can develop on the reeds causing them to be out of tune.
I would also imagine that your breathe control cant be that good all the time to not be a few cents flat at times.
I have noticed a slight mistune on some reeds while playing. Mainly when I have an excess of spit develop. It's a problem I often encounter, and it really frustrates me to no end. Usually it winds up causing an outright reed jam that I have to try and clear while I'm playing. Does anyone have any tips on how to reduce my saliva production while playing? ----------
I have one harp that I embossed and gapped. If I play it for a few minutes, I lose a couple of the overblows. If let it air out, it is fine again. My theory is moisture is the problem, maybe combined with the reed tolerance.
Cool ambient temperature & warm breath = condensation. I've just tuned a harp for a customer and the temp. here in London is only about 55f and the heating is not on. A slow gentle breath causes suprising amounts of moisture on the reeds. next time you have a harp apart check it out.
It's another reason why harmonicas have always been tuned sharp.
They will make them flat a little because of how the moisture collects - always on the rivet end (weight there makes em flatter, as you know). It collects there while the reed is in motion, because moisture gets kicked off the free end of the reed, but not there. If you play with a dirty mouth, moisture isn't the only thing that can collect on that part of the reed. I had a B-radical come in a few months ago, that I thought I might have to replace 10 reeds in it. Actually replaced zero. This nastiness, which had collected on the reed with the moisture, plus stuff that had grown there on the reed, had caused all these reeds to go flat by more than a semitone. This was when I created the "Legendarily Grimy Harp" surcharge for cleaning ;)
Of course, if your mouth is clean, none of this happens. ---------- David
____________________ At the time of his birth, it was widely accepted that no one man could play that much music so well or raise that much hell. He proved them all wrong. R.I.P. H. Cecil Payne
I recently bought an ultrasonic cleaner which I frequently use to keep my harps clean. Not that cleaning is going to prevent moisture, but it stops gunk buildup and reeds from sticking.
@ Dave Payne: I think you might have that wrong! I know, I know! :) But believe it or not, this is something I've actually experimented with. I use blue tak to bring the pitch down by putting a dab on the TIP of the reed. So I thought that putting a dab at the BASE of the reed might bring the pitch UP. Well, I was right, BUT, not THAT right. Turns out that even a large blobs of blu tak wasn't enough to raise pitch by a semi tone. ----------
529hemi: The context of tuning a harp is a lot different than playing it. When you tune a harp, you need to get the reed to sound to a specific pitch with t a very narrow margin of error. There are a few things that can affect the pitch of a reed by a greater margin than that. For example breath force, condensation and not to mention the precision of your tuner.
To tune a reed, you typically scrape metal off the tip or base of the reed to make the pitch go up or down respectively. To assess whether you got it right, you typically play the reed once or twice. The trick is to make sure that the reading you are getting on your tuner from those two breaths are accurate. So you need to make sure your breath force is constant and that you are not playing too hard.
Condensation can affect the pitch of the reed in the context of one or two breaths. That is, when the temperature of air drops, the humidity precipitates. However, once your reeds are warmed up, this doesn't happen any more.
So condensation from your breath is only a problem when you are tuning your harp, since you are making a decision about how much metal to scrape off based on what you think is a very precise measurement of the pitch, but that measurement can be skewed because the temperature keeps dropping. It drops every time you put the harp down on the table to file the reed you are working on.
The air that comes out of your lungs is 100 per cent saturated with water and is at 37 degrees C (body temperature) This is constant. In the context of playing with a band, I reckon your harp reaches a steady-state fairly quickly with respect to temperature so that you don't notice the differences in pitch between the first few notes you play while the harp is cold and the subsequent notes of the warmed-up reeds.
Spackle20: What kind of harp? An unsealed wooden comb that warped when it got wet could possibly be causing the problem you describe, but I think it pretty unlikely. I don't think moisture would affect the reed performance in that way.
This is a great video on how to adjust your reed's shape:
Of course! Why did it never occur to me?! Plus, it'd give me a nice blue complexion. Folks will be saying "That dude is so cool....he's literally turning blue!" ----------
The formula for the vibration of a spring mass system, like a reed, is;
frequency = square root(spring rate/mass)
In a reed, the area near the root acts like the spring and the area at the tip is the mass. Some areas are both, so the math gets complicated, but in general, if you add weight to the tip you are changing only mass. Remove mass and the frequency goes up (sharpens). If you scrape material from near the root, you are reducing the spring rate, making the spring softer and easier to bend, so the frequency goes down (flattens).
The blue tac you used in your experiment does a good job of adding mass at the tip so it is effective in lowering the pitch. It does a poor job of stiffening the spring at the root so it does not have much effect at raising the pitch.
I can see David's point about moisture getting thrown off the fast moving end of the reed, but moisture at the root (rivet end) will have little effect on pitch.
Last Edited by on Oct 10, 2012 8:22 AM
