G from Harp On! © 19 August 2001
MAIN PAGEThis document is not gospel, it is a series of beginner guidelines of "How To's". Reed replacement and good reed adjustment can save you a lot of money. For books & material on the "How To" start with Doug Tate's "How to Make Your Harmonica Play Well", simply because it is a good book on harmonica maintenance, it only touches briefly on reed adjustment.
The Lee Oskar tool kit is also worth buying for two things - the brass "regapping" tool, and the instruction booklet. The brass regapping tool is almost an essential part of my kit and has been useful for countless things - it gets into places nice and neat - and with care can avoid a lot of otherwise difficult fiddly work around the harmonica.
And... download Pat Missin's awesome "Altered States" and dive into "REPLACE.TXT" and also I recommend reading "TUN.TXT" the entire file contains a wealth of information regarding tuning, tuning layouts and reeds that I haven't seen anywhere else. It's free!
After that it comes down to lots and lots of experimenting on cheap harps and making lots of mistakes, asking questions and finding the answers for yourself.
Search Harp-L, HarpTalk & Harp On! email group archives, just about everything related has been discussed at length.
It takes lots of practice, observation, comparison, experimenting and time. That's what makes the biggest difference: Once again observation, experimenting, trial and error is the best way to gain experience.
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First things first.
Work with good lighting and a good WHITE work bench at about chest level and a strong pair of reading glasses or a jeweller's loupe.
Daylight is far better than any form of artificial lighting. A good "daylight bulb" is a fairly decent option if there simply isn't any real daylight.
Reed gapping is much better termed ~Reed Adjustment~.
It isn't just the distance between the tip of the reed and the top of the
reedplate - it includes the entire profile (thickness),
the length of the reed from base/root to tip as well as it's
three dimensional shape and attitude or arc.
It's very important to keep this in mind.
Too many people tend to focus on just the tip of the reed. "Profile" is the physical distribution of metal over the length of the reed and is determined during the milling process and can only be changed by physically adding or removing metal. "Arc" refers to the curvature (or lack thereof) of the reed this is what is changed during reed adjustment. "Gap" refers to the distance of the reed from the edge of the reedplate at any given point. Generally set the "arc" first and then do the gapping.
A reasonably good starting point for beginners:
keep the entire reed just above the reedplate,
set the end gap about the same as the thickness of the reed.
The point is to avoid having the reed dipping below the reedplate surface.
This is not law, not gospel, just a good starting point.
Also, from the root of the reed to about 1/2 way to 3/4 way along, each reed should maintain a low gap, even almost level with the reedplate. From that point on to the tip there should be an ever so gentle curve up to the final tip's gap point. No bends or sharp changes.
One very important thing to avoid is having the reed rise in the middle and slope downward towards the tip. This reed shape can sometimes be the result of poor tuning technique and is guaranteed to ruin the response of the reed.
The lowest/longest reeds have the widest gap,
shortest reeds have the smallest gaps,
the real small ones are very finicky,
fractions of a millimeter
change the way they react.
The big bassy suckers down the end with the extra pad of thickness at the tip,
they have to be gapped even wider than the others.
One general guideline that is often used is to make the distance between the tip of the reed from the reedplate about the same as the thickness of the reed tip itself. This is only a guideline, but it will help get you into the ballpark.
For diatonic harmonicas, there should be a slight difference in gapping between the two reeds in each hole, set the lower pitched reed in each chamber with a bigger gap than the higher pitched reed.
The lower pitch reed should not be gapped in a manner that it chokes based one's playing style.
Compromises have to be made based on a harp player's playing style. That's why there is no set rule for gapping distance, only guidelines. One man's gap is another man's choke hold.
So, if you are having trouble with the draw bends in the lower of the harp, or the blow bends in the upper range, it may be worth widening the gap of the higher pitched reed. Also, if you wish to get easier overblows and overdraws, then you will need both reeds to be gapped a little closer than usual. If you have a partially valved harp, such as the Suzuki ProMaster, then the reed that doesn't have the valve fitted will tend to require a wider gap than the reed with the valve. Often people complain that they can't get the "extra" bends on a partially valved harp. Usually this is due to the valved bends requiring slightly different technique to the usual bends, but you can help them along by widening the gaps on the first six blow reeds and the top four draw reeds.
But when all is said and done, the only way to make sure that the gap is set properly is to play the thing. If a reed stalls under high pressure of sharp attack, then it needs to be gapped wider; if it feels leaky to play, or you can't get a clean overbend, then it needs to be gapped closer.
From here on observation and trial and error play a huge part, there are some other theories of giving you a starting point, but in the end there is still a learning curve, as reeds behave differently and experience is the best teacher to how to solve individual setups. Using one's eyes and close comparisons, being really specific and using small adjustments and frequent tests will render satisfactory results quicker than doing big adjustments and less testing.
Basically from the bass/bottom end set the reeds using a progressively smaller and smaller gap. Use the reed thickness as a basic guideline. Aim to make as smooth as transition in gapping between all the reeds as in the variation in gapping should generally be a gradual slope from one end to the other. The exceptions to this are where there are pattern changes in the harmonica's hole layout, or with higher pitched reeds on the diatonic.
Usually I do the top reeds until that hole feels right, and the bottom reed until that hole feels the way I want it. Then work my way from low end to the high end, since it gets fiddlier as you get near the top. Once they're basically set, then I really go all over again comparing neighbouring holes for response working low to high aiming for equal responsiveness from hole to hole.
Avoid jumping all over the harp when adjusting. Its ok to gap the high end first since they are the most difficult reeds to bend but then start with the lowest hole and work your way up the harp.
When you are finished gapping there should be continuity in the gap pattern. Either all the reeds are set equal on the plate (overblows or light playing) or gradually descending lower in the slot from the first to the last hole (medium to hard playing).
If the gap on say, hole 4 draw is higher than hole 3 draw or the gap on hole 5 is lower than hole 6 after you adjust for smooth bends then there will be a problem with the playing action.
Optimum gapping provides for
Keep in mind when you look at a patch of grass in a paddock, it appears as a patch of grass & earth in the middle of a paddock. If you lie down on your front and watch that same patch of grass and earth for a long time all of a sudden you start to notice a lot of things, the different blades of grass, changes in colour, the bumps and falls in the earth, the way the grass has grown from the ground, bits of tiny this and that mingled amongst the dirt, and then you start to notice the ants, the insects and so on ... the longer you watch and really pay attention the more that comes to light. THAT is part of the secret.
If you adjust a reed perfectly by sight or by feeler gauge, but it still doesn't quite play properly, then it is not perfectly adjusted.
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With patience, care and 100% attention. Sober & without distractions. Start on a bunch of cheap harmonicas you can destroy as you learn.
A feeler gauge 0.008" or under is an excellent tool.
Be careful when using any feeler gauges. In fact, be careful whenever you are working on reeds! To start with gently slide it under the reed flush with the reedplate, carefully ~almost~ up to the root of the reed to get the 1/2 to 3/4 reed flat then upward slope.
To do this place your finger on the reed with the feeler gauge flat underneath, have the tip of your finger about where the rise begins and slowly bring up the tip of the reed using the feeler gauge. Again use care, patience and lots of looking and checking. Don't force anything too hard.
For gapping use a regapping tool, a tooth pick or something slim, smooth, straight & sturdy, gently manipulate the reed close to the BASE of the reed to push it up or down making a smaller or larger gap. Then you avoid changing the shape of the reed. You can alter the reed's arc by gapping from the tip.
Use lots of little gentle pushes rather than trying to force it in one go. It may take fifty tries to get it right ... if it takes five you may have pushed it at right angles in the process! Not a good plan. Also play the note checking it, this will also help the reed settle in after being adjusted.
With diatonics, checking how gapping feels to play without having to reassemble the whole harp can be done by simply holding the whole affair unscrewed pinching between your fingers. Use both cover plate press hard where the cover bolts go to get a reasonable airtightness. If its leaky you may have to resort to using a couple of reedplate screws around the hole you are testing.
For chromatic harmonicas, while you've got the plates off replace any
dud windsavers first.
Regapping is best done with windsavers on as the valves themselves make quite
a difference to how the reeds work. Generally speaking,
valved harps require their reeds to be set slightly higher than unvalved ones.
Again for testing hold covers on at the corners, if its leaky put a couple of
reedplate screws in around the hole one at each end to avoid buckling the
reedplate. I leave the mouthpiece/slide assembled for this sort of thing.
For either type of harmonica you will need to put both the plates and covers on to check the action of the whole harp later.
Altering the adjustment of the reed often alters the pitch slightly. Likewise, retuning the reed can alter the adjustment. Refer to Pat Missin's "Altered States" for more information on tuning.
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Anything beyond beginner level really is a matter of practise, comparing what works against what doesn't work and experimenting ... hours and hours and days, weeks, months ... of twiddling and testing and trying. Use your eyes, observe and compare a lot. Trial & error.
Patience is the big secret in everything harmonica techs do. Patience to stick with it until its right, not almost right. Patience to learn from our mistakes and not quit due to mistakes. Patience to observe and understand reed mechanics and profile until its ingrained in their minds.
That is what makes the guys who do this stuff so good, not the "secrets of the trade".
There are "secrets of the trade", but before they are of much use to anyone, one needs the grounding and experience FIRST!
Personally I'd rather buy a decent instrument that doesn't need gapping or get an expert to do it. But even the best made harmonica may not be adjusted to a player's style and preferences.
Reed replacement and good reed adjustment can save you a lot of money.
And anyway I wanted to be able to buy a stock instrument and make it reasonably playable. When you can do it, its a neat gift to share with other harmonica players. I love being able to take apart an instrument that has caused a player considerable fustration and in an hour have something that has them rapt with it.
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© 2001, Written by 'G'
harpon@bigfoot.com
https://www.angelfire.com/music/harmonica
For their additional comments,
technical corrections & proof reading many thanks to
Pat Missin
patm@freereed.net
http://www.patmissin.com
Mike Easton
FatHeadMI@aol.com
http://www.harmonicarepair.com