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Dirty-South Blues Harp forum: wail on! >
What makes a reed broken
What makes a reed broken
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johan d
5 posts
Jun 18, 2015
10:50 PM
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As a beginner...
What's does get a reed out of tune?
Why does a reed get's broken?
How to be sure if a reed is broken?
Last Edited by johan d on Jun 18, 2015 11:05 PM
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STME58
1341 posts
Jun 18, 2015
11:20 PM
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In my experience, the first sign of a broken reed is it goes a little flat, then suddenly it goes a lot flat. You can file it and bring it up to pitch but it will go flat again in a few minutes playing. Many times when you try to gap a reed like this it just breaks off. The most common cause of a broken reed is fatigue, the harder you play the harp the less time it takes to reach the fatigue limit. I have not had it happen but reeds can break on a draw and end up in your mouth. There is even a US patent for a harmonica with a reed catcher to keep you from choking on a broken reed! It is not a good idea to ignore a draw reed as it goes flat.
If you want detail of the fatigue failure, see this thread; Reed Failure
Last Edited by STME58 on Jun 18, 2015 11:21 PM
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WinslowYerxa
887 posts
Jun 18, 2015
11:29 PM
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Reeds go out of tune from several causes, but one of them is metal fatigue caused by stress.
While metal can have defects, the usual cause for a reed to stress, go out of tune, and finally break, is to give a reed energy that it can't fully dissipate in normal vibration.
If you play a reed too hard, beyond its capacity to vibrate without damage, it will fatigue.
If you tune your mouth to a note that the reed can't play, it may squeal, shudder, or make moaning sounds, all of which stress the reed.
Note bending is the art of getting a reed to play a different pitch from the one it's tuned to, by shaping your mouth so that your mouth tunes to that note. If the note is within the range of notes that the reed can produce it will comply, even with gentle persuasion.
However, if you try to bend a reed's pitch down too far, beyond its ability to respond, the reed will stress, go out of tune, and eventually break.
If you bend too far while also playing with too much breath force, it will break even faster.
If a reed goes slightly out of tune, it can often be tuned up and work well for a long time.
However, if the pitch goes down significantly and does not respond to tuning, it will eventually dive down into its slot and fail to spring back as it normally would. When it does this and you try to lift it out of the slot, it will usually break off near its base (the part that's fastened to the reedplate with a rivet).
When a reed goes out of tune and I suspect it may be ready to fail, I do what I call the 100-plink test. I lift the tip of the reed with a stylus, just enough so that it will vibrate when I remove the stylus. This typically results in a sound something like "plink," hence the name. I plink the reed rapidly 100 times. if the reed is near failure it will usually do so during the test.
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Winslow
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Leatherlips
335 posts
Jun 18, 2015
11:54 PM
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This has now been more than adequately explained and how to prevent it from happening.
The usual material used in manufacture of the reeds is bronze, but if you want to pay more money, you can buy harps with stainless steel reeds which will last significantly longer, but the best thing to do is to change your style of playing so as to not over stress the reeds.
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STME58
1342 posts
Jun 19, 2015
12:28 AM
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Steels have what is called and endurance limit (a stress below which fatigue will never occur) and brasses do not (they will eventually fail, it just takes a LOT longer at lower stress rates). In my experience, stainless reeds fail at similar rates to brass. All this means is I am blowing the steel well above the endurance limit. I am getting better and all my harps are lasting longer, both the steel and the brass reeds.
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jbone
1968 posts
Jun 19, 2015
4:18 AM
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I have to agree with the guys above. I used to kill a reed very fast, sometimes in one or two evenings of playing. I was working with high volume bands and using a low powered amp. The tendency was to try and play louder at the harp so I could hear myself. and sometimes that #4 draw just seemed to beg to be drawn way down. Too far down! I don't know how many harps I ruined playing them too hard.
Initially I blamed the harmonica as being not well built enough. Later, after many experiments with different brands and even some custom harps, I had to face facts. I played way too hard. So I began to try and respect the tiny brass reeds for what they were, delicate parts of a great instrument.
I had to change a bad habit, which was obviously trying to pull too much air across the reeds. So I did that. It also meant I needed to find bands and partners who didn't play way too loud. Added benefit, I get to keep my hearing!
I mostly play in a duo these days, but in a band situation either the volume stays reasonable or I have to go.
At one point not too many years ago I lost some mid and high range hearing while I was also blowing up reeds. Answer I though was a bigger amp, so I got a Bassman replica and learned how to pump out a lot of sound. But my hearing still suffered. Sold the amp, got a Vibro Champ. Committed to the duo thing. It's much better.
Also the last full band I worked with could not get my vocal volume right and I got a polyp on my vocal cord.
I quit those guys and had to take a 3 month no singing break. Torture.
My harps are lasting a long time these days although I do flat a reed here and there. My voice is stronger than ever. The duo is the best thing I've ever done.
The VERY FIRST change was to relearn to play a harp with less force. All else followed that single thing.
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RSleigh
10 posts
Jun 19, 2015
10:15 AM
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A little time spent with a tuner like the istrobosoft on an iphone will give you a lot of information about how far you are bending notes and if you are "hitting the floor" and still trying to drive the note further down beyond its range into heavy stress land
most of the reeds I replace on repairs are 4 & 5 - the 5 draw only goes down a quarter tone but even if you know that you may have a tendency to try to drive it down to the half step
Plus blue notes tend to be flatter than standard semitones
If you can develop a better sense of what it feels like when you are pushing a bend too far you will start the process of dialing back. One big clue - it feels a lot more relaxed when you are playing within the range of the reeds
i read a definition of the word relaxed as using only the right muscles with just the right amount of engagement to sustain the posture or activity you are doing - no more, no less... this applies to all aspects of playing the harp, improves your tone, and makes your reeds last longer
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mlefree
314 posts
Jun 20, 2015
10:13 AM
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Great responses from some true experts! There's lots of science and practical issues like factory tuning scratches that enter into the reed failure discussion. But like jbone, I think much of that can be side-stepped by simply playing softly.
I'd just like to expand a bit on something Perfessor Yerxa said: "Note bending is the art of getting a reed to play a different pitch from the one it's tuned to, by shaping your mouth so that your mouth tunes to that note. If the note is within the range of notes that the reed can produce it will comply, even with gentle persuasion."
Many players, especially new ones, don't take advantage of the pure physics of producing sound with the harmonica. Some actively fight the laws of physics and the result is broken or failed reeds. My aim here is to eliminate ignorance of those laws of physics as a cause of such lost opportunity.
Seasoned players have learned to adjust the size of their oral chamber and airways (via the "yawn" throat position) to each note played. Like most other aspects of learning to play harmonicas, this takes time and practice before it becomes second nature. One good thing is that better tone is a by-product of doing that.
But the real pay-off is less stress on the reeds. It requires greater air pressure if you try to make a reed sound at its natural frequency without appropriately adjusting your oral cavity. That greater air pressure translates to increased energy that must be dissipated by the reed somehow, somewhere. That's where those pesky file marks that are the legacy of the factory tuners come in. They're the weakest points along the reed and hence convenient spots for the reed to fail. Even if the tuning scratches were absent (some customizers extoll the virtues of sanding them smooth), somewhere on a microscopic level is a weak point in the reed that excess energy will find.
Call it "gentle persuasion," "playing softly, "relaxed playing," they all mean the same thing. The benefits of relaxed playing are enhance by doing what Winslow said.
For further information on the scientific basis for this check this Wikipedia article (OK to ignore the math).
Helmholtz Resonance
Michelle
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Last Edited by mlefree on Jun 20, 2015 10:15 AM
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STME58
1343 posts
Jun 20, 2015
10:56 AM
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"(OK to ignore the math)"
It's also OK not to ignore the math. If you use the volume of the reed chamber as the neck of the resonator and calculate the volume of the cavity required to get resonance at the note you expect out of that chamber, you will see that the required volumes are in the range you can set your oral cavity to.
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MP
3286 posts
Jun 20, 2015
3:18 PM
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You guys pretty much covered everything re-reeds going bad. I can add only one thing. If a reed is a 1/2 step flat it is a complete waste of time tuning it up to pitch. Yerxa's plinking test -described above- will surely snap the reed in question.
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I'm out of the Biz for a while till I get over my burnout. You can try HarveyHarp or arzajac, or just look the page nacoran put together under Forum Search.
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SuperBee
2705 posts
Jun 20, 2015
6:48 PM
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I've been replacing a bunch of 7 blow reeds on G harps. Some are not really all that flat and if they were mine I'd just tune them. I'm replacing them all though, and even those which are only 10 cents below 442, (but I'm guessing they've dropped 20 cents on the factory tuning) show clear signs of damage to the reed.
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