Jump to content

Dana Johnson

  • Content Count

  • Joined

  • Last visited

About Dana Johnson

  • Rank
    Heavyweight Boxer

Profile Information

  • Gender
  • Interests
    Playing ITM and making concertinas
  • Location
    Kensington Maryland. USA

Recent Profile Visitors

825 profile views
  1. Muffled reeds probably aren’t dust related, though the stuck reed may we’ll have been. On a new concertina, I wouldn’t expect a loose corner block in the bellows which can cause reeds close to it to be weak, but overly stiff flap valve leather covering the reed ports in the reed pan often can muffle reeds, especially when new or just from a stiffer part of the leather they are cut from. Sometimes just playing these reeds harder for a while can help the valves flex more. A jet of air will generally cause the valves to flex a lot, but as they come back to rest can redevelop a set in that position. So many problems can be traced to valves. Other things can cause reeds to be muffled, but not ones I can think of that would be temporarily cured by a jet of canned air. Dana
  2. The torsion spring is very simple, but these are the things you need in your design: there are two grooves in the bottom of the hand rest. The separation between controls the torsion created. The separation I use is about 1/4 inch which for the 302 stainless spring wire I use is quite good. The arc on the butt end of the hand rest needs to be at least from the radius of the short leg, or even slightly more curved so the crossing part of the spring gets farther from the hand rest as it swings up. I just used a compass to draw it on my templates from the rear most groove. The spring is bent all in one plane, and when installed already has the needed downward tension. My springs are about 1 inch - 1-1/4 inch OAL, which also works with the separation distance to control torsion. I chose it because it had a good spring tension over the working distance and looked good in proportion to the hand rest. I instal them so that the long leg is on the side of my hand rest facing the wrist just because it looks cleaner to me. You also need to remember to make the legs long enough to allow for the strap thickness. ( a bit obvious, but you never know ) Dana
  3. Hey Chris, that one sure deserves to be shown off! Even in this limited view, it is one of the nicest I’ve ever seen. Wish we didn’t live at opposite ends of the earth. D
  4. I once played a Jeffries with 3mm buttons. It was a terrific sounding instrument, but like sleeping on a bed if nails. Even though I use 6.35mm buttons on my concertinas and like the feel of them, I think 5mm is a good size. After a certain point, you have to start worrying about the space between buttons which gets smaller when the buttons get larger. When you make bone buttons, it is a lot easier to find sections of the bone that are big enough for smaller diameter buttons. I made a 6.35mm set for a customer that were really nice, but finding straight and thick enough parts of the cow leg bones was quite a job.
  5. Some musicians say each key has it’s own character, some people with perfect pitch describe each note as being distinctive. I don’t understand it, but I do find that I am particularly partial to the key of F. For me, things seem to sound more beautiful there than in G, even though I don’t generally transpose tunes commonly played in G. I certainly am much more familiar with G playing but have been pleasantly surprised when I try tunes out in F. I don’t know how true it is, but my understanding is that East Clare is known for tunes in F and Bb.
  6. Sounds more like a binding button, or lever pivot, pad sort of problem. Not knowing the construction, I can’t guess which part/s are the cause, but notes that fail to shut off When the button is released usually indicate a pad that fails to return solidly over the pad hole. sometimes springs lose their pre load tension and while they seem ok when you press the button, may actually provide little or no pressure when the pad reaches the pad hole. Also, pads that are coming loose or levers that tend to tip a bit sideways so the pad hits on one side first and comes to rest either partway off the hole or with one edge lifted slightly. Often playing a draw note after the sticky one will help suck it closed while a press note following may inhibit full closure. Binding at the button In Chinese boxes is not usually from tight bushing around the button since mostly they don’t have any. Here, buttons that are not free to move where they attach to the lever can end up rubbing against the button hole which makes the spring have to fight friction, not just hold down the pad. These are the places I’d look. Actual reed valves on the reed blocks ( for accordion type construction generally used in Chinese instruments ) generally don’t cause this symptom. Even when they come unglued and fall off the reed plate, it usually makes the note weak, or gets jammed under the reed tongue resulting in no sound at all.
  7. Know what you mean about the high range of the c/g. When I play by myself, I play my A/E for it’s lovely sound. Trouble with G/D/s for ITM is that it shoves most of the melody for most of the tunes to the right hand if you are playing with others. Great for developing dexterity, but you still end up in the squeaky range. You can play everything an octave lower of course, but you’ll run out of range on the low end for a lot of tunes. There are a few low pitch baritone C/Gs out there, but in general, low is slow. Not a problem playing with easygoing friends or by yourself. Remember, flutes, fiddles, button accordions are all playing these tunes at the same pitch. ( whistles are usually an octave higher). The advantage of all these instruments for folk music is the combination of capability and portability. I am just guessing, but I expect that the incredibly widespread use of folk instruments in this general range across many cultures is that they physically fit in people’s lives. Regarding ITM though I do admit knowing hundreds of Irish tunes who’s b parts live almost entirely on the first two buttons of the right hand g row (f#-b) pretty much squeaky range☹️ Dana
  8. Even cheap concertinas are too expensive to have one for each set of keys. Beside the general habit in ITM of playing a set of tunes that often are not all the same key, or the numerous tunes that have more than one key between the parts, or even go up the scale with a C# and down right after with a C natural. With a 30 button c/g, if you want to play in g, then in d, all you have to change is using the c# button instead of the c. I’ve been teaching Irish concertina for many years, and find my students find the fingering challenge relatively minimal. 30 button c/gs give you pretty much the same range as a fiddle, and the ability to play in the many different keys and modes in Irish ( and other kinds ) of music. A flute player friend of mine got a c/g concertina specifically to let him play the scads of tunes that go below the low D on a flute. Low G/D’s push you to play most of the melody on the right hand, and are often slower in response At least for the lower notes. I have never seen a D/G,( only a fourth apart, where the normal interval between the main rows is a fifth) though Bob Tedrow had a reversed G/C which had the C row as the inner row and the G as a middle row. He was good on it, but it threw me for a loop! I think he said he’d copied that layout from a German concertina, but doesn’t make them like that normally. D/As are pretty common and are nice bright instruments but then you might bemoan the abundance of G#s. Some ITM players do have Bb/F concertinas so they can play in “C” sessions where all the tunes are a whole tone low. but they use their C/G fingering. 30 button anglos are pretty much chromatic, but the range counts. For ITM anyway, It wants to cover the range of as many tunes as possible. I am obviously in the 30 button C/G camp, but not without good reason. You won’t go wrong with it and may discover the thousands of tunes not in g or d. I put G# thumb holes on all my D whistles so I can easily play in A. In general, the “easy keys to play on a C/G are G,D, C, A, F , Bb. E is a bit harder but more common in Scottish music. C is actually a little harder than G since it tends to force you to play more just on the middle row, where G partakes of both rows and gives you more flexability. D is easy as well. All of them just take time to learn the scales. The fingering varies between them, but doesn’t present any real obstacles. The World of Irish music is so much bigger than G and D. Your flute and whistles have their natural limitations, but that needn’t carry over to the music in general.
  9. For all of my overseas shipments, I include a complete list of materials used which I can provide others if needed. None are cites restricted. It is good to be aware of this though since not all customs officials know much of anything about materials. Glad to hear they are lightening up on the rules though, good intentions with some unfortunate side effects. Dana Johnson Kensington Concertinas
  10. For c/g Jeffries layouts, the first button is eb/c# (press/draw) and the second is c#/eb, though I have seen a few instruments that have been reversed. Wheatstones and Lachenal layouts have only the one c# / eb. With the c# on the press. If you did this years ago, clearly it works for you. What else matters? Dana
  11. I started using this style retainer for the hand strap with my first Concertinas in 1993. I copied it from a snatch hook used to keep the rope from coming off the hook while lifting things. This unequal leg torsion spring has been around in various uses for a very long time, though not on Concertinas. Harold was very kind and asked me if I minded him using the design, which was fine with me. It works well, is fast to change holes on and is very secure. The key to it is the unequal length of the legs, which swing through different angles when lifted, putting a torsion force on the part of the spring that connects the two sides. If you like it, use it. Public domain as far as I am concerned. I called it the strap-o-matic just for fun.
  12. Greg has really good advice re exercising. One quirk of concertina playing is that most people hold one end fixed when seated and move the other. This means that one arm is basically doing isometric exercise while the other is dynamic exercise. It is a good idea to intersperse some moving exercise for the static arm with your playing practice. Otherwise, you will develop strength but not range of motion that can cause trouble, especially in the neck and shoulder since any force you apply has to be countered by an opposite force on the other end of the muscle attachments. Playing concertina can be enjoyable enough not to want to stop. Then all of a sudden it starts to be painful and requires a long break to get back to where it is safe to play again. Dana
  13. Hi Tom, I haven’t been following this that closely and missed the request for clarification. When I make a set of reeds, there are a number of things that are important to me as a maker. First, the reeds all need to respond at the same starting air pressure,. Second, they need to do this at as close to the same spot in their pressure-volume curve so the reeds individual dynamic ranges are in sync with each other. Given the extreme difference in reed length and area, perceived volume of the individual reeds need to be as close as practical to each other so that larger reeds don’t overwhelm smaller ones. While a reed of a given pitch can be made within a wide range of length/width aspect ratios and with a wide range of lengths, even without varying the material, by adjusting the overall flexibility of the reed tongue and how the moving mass is distributed along its length, (reed profile ) the playing requirements listed above severely limit what is actually practical. When I talk about reed stiffness, I am referring to the amount of force required to deflect it by a certain defined amount. Another term for this is spring coefficient. Since I don’t think this number is linear for flat springs like reeds, I measure it for 2 degrees of deflection on the bold assumption that such a small deflection will be in a more linear part of the curve. I have found that a stiffness curve for MY reeds that starts at about 14 gm / 2 degrees deflection for c below middle c and reaches a high of around 20 gm/2 degrees for mid range reeds about e above middle c to d an octave above that then dropping to about 8 gm/2 degrees or less at g6 on a c/g Anglo. It looks like a shallow bell curve, with each reed being close to the ones on either side. This distribution makes for reeds that all sound like one family, whose harmonic content changes similarly as playing volume increases. Other ranges are perfectly possible depending on what the maker is after. Accordion reed are matched with each other to make lighter or heavier sets for similar reasons. In making a reed, I start with a blank of a given width and length that fits the concertina, has been proven to produce the right volume for balance, and then adjust the thickness profile so that it has a finished pitch, a smooth bend, and an overall stiffness that allows it to respond properly with the rest of the reeds. No reed profile ( of mine anyway) is straight. Low reeds are thick at the tip, thinner in the middle and going back to thicker at the root. Middle reeds have a little thinning in the center and high reeds are very thin at the tip an thicker at the root, but not in a straight slope. There is a neutral place in a reed where varying the thickness balance the pitch lowering of reduced stiffness and the pitch raising of reducing the moving mass. I use this area to adjust the stiffness of the reed to fit on my curve. I am sure that a set of formulas could be created to describe the profile curve, taking into account the mod of elasticity of the material, it’s density, along with some way of scaling for volume at a given pressure, aspect ratio etc., but there is a range of possible solutions that work. When trying to make a mathematical model, choosing the simplest reed possible in order to see how the materials compare, having two reeds that have things like length width and deflection and pitch at a given pressure in common sounds like a good challenge, certainly beyond me. I know that side clearance has a strong effect on tone, but I don’t know how the traverse time of things like the reed tip effects tone if it is thicker or thinner. What I can’t figure out and hopefully you can is whether the differences in stiffness and density of the different reed materials varies how they vibrate, or simply force a different geometry in the reed that changes how it traverses the window. Best wishes, Dana
  14. Besides the fact that I’m pretty sure GB had not gone metric when these reeds were designed, keeping the heel distance the same allows consistent use of clamp blocks since the front edge of the clamp block needs to be directly over the start of the reed window to avoid buzzing or other pitch problems. Consistent tip distance keeps the chamber as short as is practical, while still leaving room for the flap valve to completely cover the reed port on the draw reeds. Too short a tip distance puts the end of the port too close to the end wall. Too long a tip distance in higher notes especially makes the chambers longer than needed which can adversely affect quickness of response. Glad to see another person taking on the concertina making challenge. Dana
  15. Hi Guys, re Jake’s comment, I don’t remember making a carbon fiber reed, though I may we’ll have opined on the subject at one point. I am still reluctant to consider them on a practical level. It was enough of a chore ( months of work ) to adjust my steel reed profiles to provide a smooth grading of stiffness from the lowest reeds to the highest to get a homogeneous sounding and playing instrument. I wouldn’t know where to begin with carbon fiber. ( not to mention the self destructive aspect mentioned in 1 or 2 of this series. I do remember an incident where the carbon fiber tail of an airliner self destructed when subject to the turbulence of the wing vortices left in the air from a 747 that had gone before it.) I think Tom’s exploration is at least academically interesting if it can shed some light on how different properties affect reed vibration, especially from a point of efficiency. Since this all seems to be a result of calculation rather than physical trial, i’m Not sure it is fair to blame the raw materials for the tonal differences people ascribe to brass or steel. Listening to Johan’s sound files of a steel reed vs a titanium one, I really couldn’t tell the difference. The chart does show the different strengths of the harmonics, but our ears probably aren’t designed to distinguish between sounds that are proportionally so similar, especially since both seem to have strong odd harmonics as the defining feature of the tone. I am not sure how you can control for variations in stiffness in these models so all reeds are equally stiff at the designated pitch. Since the point of physical profiling is to take a reed of practical length and tinker with its mass distribution and overall stiffness to reach the desired pitch with the desired response to bellows pressure, I don’t know how you can create mathematical reeds of these materials that differ so much in density and modulus of elasticity so that at a set pitch, stiffness and swing amplitude you can make a comparison of harmonic amplitude. I still have no idea how the musical harmonic series is created (which it certainly is ) when the reed’s natural cantilever bar mode harmonics are decidedly non linear. Tom doesn’t’ agree with Benade’s explanation and convinced me it may not be correct, but that is as far as I got. have fun guys, my brain is tired Dana
  • Create New...