Re: [Harp-L] Repair problem Mystery? Tesla Effect

[David Payne <dave@xxxxxxxxxxxxxxxxxxxxxx>]

Ok, just got back from the ball game. Chilly night. West Virginia won 5-1. Five broken bats, little David got to go in the outfield and pick up the post-game fireworks carnage, they gave him two free tickets, which we plan to use on Redneck Night, when the General Lee (the car) will make a guest appearance and they will have Cowboy Monkey Rodeo.

Now obligatory harp content:

The mystery problem is what I call the Tesla Effect. It is rare and extremely cool.
First thing, there isn't any possibility of air leak causing it, unless you've wrapped it in plastic wrap, which I doubt. ;) It's impossible to have a leak all the way across the harp.. I have had two or three of them that did this. These were back when I was using NOS Seydel Solists, back from when they were unsealed pearwood. This had the narrow reedslot configuration that Seydel doesn't make anymore - it was pretty much the standard reedslots pretty much everybody made, including Hohner.. At first, it was all normal. Then, I customized it. When I blew on the 10, the 1 draw started sounding.Â
The vibrations from the other reeds would start the 1 draw reed going, then as the reed moved back and forth slightly, the vibrations continue to push on it - in much the same way you push a kid on a swing.... it comes back, then gets a shove, goes out, comes back, gets a shove from the vibration. Â
So why the one draw?Â
You might think that it would push the reed that was the most resonant. But the longer a reed is, the less force it takes to get it going. So, the 1 will always be the easiest to get going. Why not the 1 blow? I never did get around to really experimenting with that to find the reason behind it. It's gotta be one of two things: 1) either the comb itself affects the vibration differently for the blow reed or 2) to swing a blow reed, it must swing against gravity, but to swing a draw reed, gravity itself is actually helping, because the arc of the reed swing goes down. If you play it completely upside down (laying on your back can you do that and let me know what happens) and the draw reed still vibrates, then it can't be entirely No. 2, but is probably mostly No. 1 with a little bit of the second one at play. I'm interested in anything you observe with this.

When I had this problem, I spent most of my time not trying to get rid of it, but trying to INCREASE it... figuring if I could increase it, I could study it better and figure out what the deal was, because I was really fascinated by this at the time.Â

But I don't think that's all that's at work. There's more at work. i made many, many customs out of Seydel Solists over the years, but I only had two, at most three that would do that. So for this to happen, I think, EVERYTHING has to be just right for it to happen. ÂI tried tuning the the reeds to different sharpness and flatness in relation to one another. I tried altering the gaps, curvature, alignment, anything I could think of.Â
This was like five years ago and I had kind of forgotten about it until you mentioned it. Based on what I remember, any Âone or all of these might help:
Make sure the screws are no too tight. Make sure they are tightened in a pattern from the center out. Make sure the reedplates aren't bent the wrong way (bulging out in the center). So I think if you switch your parts around, it might stop. If that doesn't work, try altering the gap of the draw reed. I would suggest raising it. If that doesn't work, try altering the curvature of the draw reed slightly.Â



DavidÂ
www.elkriverharmonicas.com


________________________________
 From: David Payne <dave@xxxxxxxxxxxxxxxxxxxxxx>
To: Harp L Harp L <harp-l@xxxxxxxxxx> 
Sent: Thursday, April 12, 2012 5:28 PM
Subject: Re: [Harp-L] Repair problem Mystery?
 
This has nothing to do with air circulation. Nothing at all. I'll explain in more detail later, but I'm on my way out to Power Park for the WV Power opener. It's resonance and vibration. I've seen it before.Â

David
www.elkriverharmonicas.comÂ


________________________________
From: Cathal Johnson Harmonicas <cathaljohnson@xxxxxxxxx>
To: harp-l@xxxxxxxxxx 
Sent: Thursday, April 12, 2012 11:45 AM
Subject: [Harp-L] Repair problem Mystery?

Dear Harp L,
I got 4 special 20s all in the key of A major and all needing a reed on the
blow 5. So I opened them all up and replaced the reeds all at once, I then
cleaned them in an ultra sonic cleaner combs and all and reassembled them.
Reed plates and combs got mixed up but as they were all the same key and
model I though would not matter!
But on assembling them however, there is a fault. When I blow reeds 5,6 or
7, the B note on hole 1 draw sounds off at the same time!!?? There seems to
be an air leak that escapes down into this hole and activate the B reed,
but I canât find it or figure it out? I dabbed Vaseline on to comb try and
seal to no avail!!?? It only sounds/happens when the covers are on.
Is it because I mixed them up I am thinking now?
Do anybody have any idea what or how I can fix this problem or what could
be going??
They belong to a customer and I am afraid I wonât be able to fix them
properly now, having replaced the broken reeds successfully, this is the
first time this has happened. I think it is because they got jumbled up. I
thought that would not have mattered as they are all the same thoughâ???
Any feedback is greatly appreciated!!
Regards,
-- 
Cathal Johnson