GermanHarpist
1940 posts
Jan 16, 2011
9:54 AM
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So a quick tip on the side when customizing for OB. When the overblow produces a squeal I saw a guy just twist/bend the blow reed lightly to alter the natural frequency at which there is torsional vibration.
Of course this is a pretty quick and crude fix to the problem but maybe there are some other methods of changing the natural torsional frequency. Maybe making the reed vibrate easily in the length of the reed and less in the width. Some kind of directional approach.
There was one customizing technique I had seen some time ago, and it could be that this was what it's for.
The technique was to put a shim under the reed and then drag a piece of metal (like the ball of a tuning fork) over the reed away from the rivet as if you were pulling the reed. This may be to change the inner properties of the reed (besides widening the reed a little).
Thoughts?
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Last Edited by on Jan 16, 2011 1:00 PM
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jim
706 posts
Jan 16, 2011
12:29 PM
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sometimes this will help.
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Jeffrey van Kippersl
4 posts
Jan 16, 2011
2:05 PM
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Actualy, I learned from Tinus (overblow.com), it'll show pictures of how to, too.....
I use dental wax/silicon whatever it is called, the transp. one. I push it on the beginning of the reed, rivet is it(?), 1mm thin slice and push it tight, check weather theres still torsion, when there is I push it tighter and up the reed a bit more.
In my experience the solution, no more squealing, might it reappear, just push it tighter again. is use it for 4 months on my fav harp, its still sittin' tight.
By the way this takes away the annoying problem of the reeds still playing when you already put away your harp....... if this is something you dont like that is. The further you go up, the faster the reeds are going to a stop again. I use two C-Harp, both setup differently, for when playing slow, tastefull lick, I actualy like my reeds to stay on a bit longer.
Hope its something you can use...
Last Edited by on Jan 16, 2011 2:06 PM
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Jeffrey van Kippersl
5 posts
Jan 16, 2011
2:09 PM
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Forgot to say, a big part of the squealing is produced by wrong technique, when I push in the OB when playing fast, you hear the reeds tend to go in the direction of squealing... however the wax still prevents it. Anyway, technique is just as important as the wax, i think.
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chromaticblues
477 posts
Jan 16, 2011
3:18 PM
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To everyone wax deadens the reeds. Takes sustain away! Nail polish dries hard. So this helps keep the reed stable and still has good sustain. I'm not saying wax doesn't, because it does. I don't like dead sound. I like a harp that rings with sustain.
I just wanted to let people know of another way.
There are many things on Tinus's site I do! Alot of it is learning to play the harps you have.
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GermanHarpist
1943 posts
Jan 16, 2011
3:27 PM
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I was actually more looking for something inside the reed. Changing the properties of the steel.
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BlueDoc
23 posts
Jan 16, 2011
9:13 PM
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"The technique was to put a shim under the reed and then drag a piece of metal (like the ball of a tuning fork) over the reed away from the rivet as if you were pulling the reed. This may be to change the inner properties of the reed (besides widening the reed a little)."
I am not a customizer, and I have never tried this technique, but I wonder whether one reason it works, in addition to the other reasons mentioned, might be that it aligns the reed in the slot.
-Mark
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7LimitJI
312 posts
Jan 17, 2011
1:41 AM
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"The technique was to put a shim under the reed and then drag a piece of metal (like the ball of a tuning fork) over the reed away from the rivet as if you were pulling the reed. This may be to change the inner properties of the reed (besides widening the reed a little)."
AFAIK. Doing this flattens the reed out and is supposed to extend the life of the reed.
The reeds are stamped out at manufacture and are slightly curved in the process.Not end to end,but side to side.
From an engineering point of view, flattening this makes sense,as putting a curve into metal stiffens it.
It might affect the reed stability,then again it might not,I'm not an overblower.
I only started doing this recently,so cannot comment on the extended reed life.
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Last Edited by on Jan 17, 2011 1:42 AM
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apskarp
390 posts
Jan 17, 2011
4:04 AM
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For OB's the sustain isn't actually a desired quality as you have to stop the blow reed in order to get the OB. This is why people use wax, bluetack and even glued pieces of material on the reeds to make them stop quickly.
I guess you could try to make a compromise and try to get the best from the both worlds.
For me the technique GH mentioned would create a curve to the read. If the ball touches only the middle part of the reed then the effect isn't so big, but still. Pressing brass changes it's inner structure and makes it little more stiff but it also makes it more fragile. This is why customizers use heat/cold treatment to get rid of those inner tensions.
I suppose you could do that trick to both sides of the reed so that it would remain straight but still create little bit tension in it so that the torsional vibrations would be reduced.
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harpdude61
648 posts
Jan 17, 2011
6:43 AM
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This one sort of baffles me. I've never had an overblow squeal....or a slight delay in sounding.
However, I have had several stock harps to squeal on the two draw when bent down 1 step. I finally figured out this usually happens when I bend them too far...but it still should not happen.
Jeffrey is probably correct about technique.
Last Edited by on Jan 17, 2011 6:44 AM
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Joch230
374 posts
Jan 17, 2011
7:10 AM
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@askharp You need to be able to sustain the OB if you want to be able to then bend it up.
@harpdude61 Sometimes the OB will stick a second and then just pop for you...you hit the note but the listener can usually tell that something just happened that wasn't supposed to happen there!
Regardless of technique, if the harp isn't set up just right, you can still get squeal, usually when sustaining the note or playing the note at the same (louder) volume as the notes you are playing before and after it.
-John
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