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

1054 profile views
  1. I wonder what the piano thinks of being reincarnated as a concertina😀
  2. First, don’t move the reed. If you want to tighten the clearance, you’d have to shorten the tip to push it forward, then re tune by a fair amount since that pitch is reacting to such changes faster than low notes. Then you have to be sure it is properly centered, and on a Jeffries that generally had pretty well made reeds, it isn’t likely going to get you much. While Alex’s observation should definitely be checked out, I would be expecting similar difficulties with both the Eb and middle F#. Of course, the large difference in pitch will mean even with the Airyness factor, the lower reed is still likely to respond better since it is already using more air to sound, so the loss percentage will be smaller. It is also quite possible that the valve on the backside of the F# reed is staying open even a small amount at playing pressure. Bob Snope of the Button Box in his great wisdom said he found most problems with reeds go back to valves. Really, this just means that valves can cause a lot of problems, where other real problems with reeds are simply relatively uncommon. Check the F#’s valve to make sure it is lying flat or close to it, not curled up or dried out and stiff. Flap valve leathers used in older instruments especially the white alum tanned leather while mechanically had good properties, degrades over time. (It also very slowly gives off sulphuric acid vapor which corrodes the brass reed shoes it is next to. Dana
  3. Buying anything for adjusting a single concertina seems a waste unless you are going to pass it on to someone else. Makers or repairers or people who have a number of instruments they want to all feel the same, might get enough use to make it worth while. Your brain is a highly sophisticated device for comparing similar things, not so good without training for quantizing things. To adjust one spring to “feel” like the others just needs you to feel the difference which you have proved you can already do. ( if you can’t feel a difference than you are close enough ) The kitchen scale is a free way to go if you have one and is as accurate as you can possibly feel. Beyond that, Chris’s approach is a good one to follow and need a new spring. Some people want to change their whole concertina a button pressure they prefer. Even there, a kitchen scale will do. When I adjust my instruments, I use a dial gram gage but on the levers at the button position rather than the buttons themselves which are vulnerable to friction in the button bushing. If buttons feel stiffer after that, I know they are not moving freely and fix that. Dana
  4. Mahogany, especially The 100 year old sort was often used for larger instruments pad boards because of its excellent stability. It is too bad that as usual it was over harvested and the best varieties are on the CITES list. Sometimes Old large pieces of furniture like display cases can be found and can be quite a prize. Once upon a time, you could paw through the Martin guitar company’s reject pieces for some great wood. Not these days though.
  5. Plywood, birch or otherwise tends not to warp because it is balanced in its layup. If you start planing off the plies, that ceases to be the case. Even numbers of plies 90 degrees offset, tend to twist in warping as humidity changes. Because it is trying to assume the shape with the lowest area. Odd numbers of plies stay flatter. In the small sizes concertinas use, the small tendency to warp is not hard to constrain. Given that you would be changing the wood anyway, using plywood slightly thicker or thinner than the original won’t make any more difference to the sound than the change in wood will.
  6. The European sycamore (not the flaky barked patchy stuff in the US) should be easy to get. The wood I use comes from Austria anyway. I have to look through the pile for the best quartered material and the least figured. But it is excellent.
  7. When I think about it, a 4 dB difference isn’t a lot. I do think you may get a decent reduction with a long sound path, but I don’t know how that might effect the reed response. It does make a mellower tone.
  8. I thought I’d better check out my suggestions rather than just propounding on them. Here are results for a D3 reed: I did three different reed shoes and two reeds. The first reed/shoe combination was my normal low D but with zero relief angle. The reed is .123 x 1.525 inches. The reed shoe is .063 inches thick. I used this as a base line. The second reed shoe had the same size window and I used the same reed swapped out from the first one. The difference was that on this shoe I used an end mill to relieve the back of the window so it was only .025 inches thick. The relieved area was.215 x 1.525. The third reed / shoe was also .063 inches thick and the window was also 1.525 inches long. But this combination used a reed that had the identical profile, but filed to a width of .093” or a little more than 2/3rds as wide. The window also had zero back relief. Clearance and set was identical. I did two comparisons, one at 1 inch wc which is my normal tuning pressure, and one at 1.75 inches wc, which is the maximum my tuning blower will deliver at that reed’s flow rate. I arbitrarily chose to call my first reed as zero dB with the 1 inch wc, to make comparison easier. All the reeds were mounted the same way in the same chamber on the test reed pan. The results of the 1’wc test were: (Reed 1) 0 dB. (Reed 2) -4 dB (Reed 3) -2 dB. The results of the 1.75” wc test were. (Reed 1) +4 dB (Reed 2) -1 dB (Reed 3) +1 dB. the net change from 1” wc to 1.75” wc was: (Reed1) +4 dB (Reed 2) +3 dB (Reed 3) +3 dB. Both reed 1 and 3 managed to increase output above Reed 1’s 1” wc level at the higher pressure. Reed 2 increased its output but even at the higher pressure couldn’t get to Reed 1’s low pressure output. the reeds all sounded clear and not dulled in any way though I was only interested in volume this time. my conclusions are that the reed with the back relief leaving a window .025” thick reduced the volume most, being 4 dB quieter from #1 at low pressure and 5 dB quieter At high pressure. The narrow reed worked well, but was 2db quieter than #1 at low pressure and 3 dB quieter at high pressure. So far it looks like the reed shoe with the cut out back is most effective in reducing volume, and might be even more so if I had cut deeper leaving a thinner window. The narrower reed also had a reasonable effect, but wasn’t as pronounced. I found it interesting that the back relieved #2 couldn’t get up to #1’s low pressure output, suggesting that it was close to maxing out. I don’t know if a 4-5 dB reduction would be sufficient to better work as a drone or if some other way of dealing with it would be needed. ( or you could make a narrow reed with the back relief cut out I suppose ) Dana
  9. This looks like a very nice solution for that strap type. My straps adjust on the other end, so I do something similar with a nickel silver paddle that is hinged in a slot on the bottom of the thumb end of the hand rest. These things can be clunky if cobbled together, but you did a lovely job. Dana
  10. I don’t think making the reed a bit narrower will cause you much trouble unless you start approaching a width that is similar to the thickness. ( square cross section ) Reeds that are too wide can push up the natural twisting mode into the frequency range of the fundamental and cause problems. WithIn the normal proportion range that mode is a good bit lower in frequency. I don’t remember what the proportion was where that could begin to happen. Haven’t thought about it for 20 years really, but it looked like you only might get close to it in high reeds which are short for pitch, but wider to keep their volume up. Low reeds are always too long to come anywhere near that ratio. The low D in my old duet was in the range where the chambers were getting longer than the reeds. By the time you got to the low G it was half again as long as the reed shoe. It will better support the low fundamental.. those chambers were also deeper. The layout was similar to Englishes that have the shorter and longer reeds mostly on opposite quadrants of the reed pan. This meant by mounting one side of the reed pan deeper in the bellows frame than the other, but keeping the tops of the chamber walls level, the low reed chambers could have more depth while the higher ones were allowed to be shallow. Again, this allowed for a solid fundamental. Rounding the reed edges does make the reed closure less abrupt and reduces harshness, but as long as the final clearance is good, I don’t think it will badly affect efficiency. More clearance has a similar effect, but does lower the efficiency / response. In my early days, I tried making a reed that was mounted over a window in .025” shim steel that was then mounted over a full length window in a reed testing setup. I was surprised that it was much quieter than when a normal reed /reed shoe was mounted in the same place. I may try this experiment ( milling out the backside of the window ) on one of my lo D reed shoes and compare the results with the same reed in the same instrument. I’ll let you know. Dana
  11. Restrictions on a reed generally aren’t good for either sound or response. A reed used as a drone can afford a bit less responsiveness, but you still want a good tone from it. There is a good bit of latitude in designing reeds of a given pitch. The set of baritone Wheatstone reeds I have are a bit larger than their equivalents from the Wheatstone McCann duet I based my reeds on originally. Linota reeds are wider but not quite as long. A few possible ways you could deal with this are: Keep reed profile an length the same but narrower. (As mentioned earlier). That gets you a reed that still behaves like your set, but just can’t affect as much air. The stuff I’ve read on reed organs says that narrower reeds have weaker higher overtones, which could be helpful to keep a drone from walking over reeds an octave higher. You can also reduce the center area of your reed to make it weaker in the more or less neutral area which will mean it will reach it’s max swing at a lower pressure than it’s mates for a lower volume. Stronger reeds have higher maximum volume because they require higher pressure to increase their swing. Related to this is to substantially increase the reed’s draft angle which allows it to dump air before it has swung very much. The low D is normally long enough not to require more than a few degrees draft because it clears the window before it has swung very far. This sort of pulls the rug out from under the reed. You might use a small ball end mill to cut a wide groove down the center of the backside of the window leaving only maybe half the shoe thickness left for the window. Years ago, Marcus did something similar to his hybrid reeds with a v shaped cutter ( I think he asked for this from the manufacturer) in order to approximate the concertina reed geometry. It certainly didn’t hurt them, but I don’t know if they are still done like that. It was 25 years ago. A shorter weighted reed can reduce the volume as well, but gives poorer response than a reed long enough not to need the extra weight at the tip. This may not be an Important issue with a drone. overly weak or weighted reeds are more susceptible to blowing flat under pressure, but you should be able to manage fine for a low D drone. You can be quite a few cents off and still be only a couple hz off, with barely noticeable beating against any melody note more than a perfectly tuned note would create. You can always tune the drones a few cents sharp at low pressure so they will come on pitch at a bit higher pressure, yet not be too flat at full volume. Good luck. I’m glad someone has thought to pay attention to this. I’ve only seen restrictive measures so far. Dana
  12. Rich Morse had a whole set of these, though the arch at the end was more abrupt and didn’t extend too far down the reeds. I have seen the twisted end ones as well, and it was quite substantial and not at all accidental. That organ also had straight reeds, which were well made. Organs have a lot of access to air and can afford to use less efficient reeds.
  13. This is an interesting effect of tapered windows, and perhaps might be assisting in response?
  14. My two Jeffries (nw sold) both had tapered reeds with .010 difference in width from base to tip regardless of length, which gives a nice scale for percentage of taper relative to length / pitch. My Wheatstone duet and some other Wheatstones I have checked had parallel reeds, but they made so many kinds of reeds, I am not surprised by your tapered Aeola reeds. One thing that needs to be taken into account, is that tapering a reed is a close equivalent to a reed profile that is thicker toward the root. If you simply increase the width of a parallel reed, you just make it a stronger spring, but don’t change its pitch. If you only increase the width towards the root, you add greater stiffness overall, but without the compensating mass at the tip, so all else being equal, the pitch will be higher. Because Increasing thickness increases stiffness faster than increasing width does since more material is farther from the center of bending, it isn’t strictly identical to changing the reed profile. What I think is important, is that tapering a reed allows you to have higher reeds being longer than they would be if they had been parallel at the same pitch and overall stiffness. Since large lower reeds are generally louder than small reeds, having longer and hence larger high reeds could help with balance. This isn’t too much of an issue for instruments with the range of a c/g Anglo or a 48 button treble, but on a duet or even something like a 56 button tenor treble, the difference in size between low and high is more extreme and you start to see efforts to decrease the output of the lower reeds. I have been fitting reeds for a long time, and find no need to adjust the fit with anything but a rather large file. It is pretty easy to hold a large file straight and I found it took very little time to get a feel for how much bite the file is taking. Adjustments of .0001 inch are normal. Using the taper to fit the reed does work well, but I don’t think that was the reason it entered reed design. Tone of different reeds in different concertinas is a tough nut to crack. Different models can have construction details and materials differences that can dominate the sound, so it may be hard to pin the tone on the reeds alone. But, in reed organ literature, longer narrow reeds are said to be less bright than wider reeds. Wheatstone made a type of reed where the side edges were rounded, and were advertised as a better class of reeds. Those kinds of changes can be tied to the reeds more easily. Same for short scale vs long scale reeds. Just because tapered reeds are a combination of narrow and wide, I wouldn’t be surprised if they tended toward brightness. From looking at reed waveforms, I’ve seen the higher pitches having more Sinusoidal wave forms, and perhaps they benefit from the extra brightness. Since this is so prevalent in the accordion industry, it would be interesting yo hear their take on it. Dana
  15. That pattern of “dishing is caused by the actual bending of the shoe crosswise against the reed tongue. Those small screws can exert a surprising amount of force. I once used .063 hard brass for my reed clamp blocks, but found they actually bent visibly over the reed. The .093” I use now doesn’t bend appreciably, but the reed frame does slightly bend up at the screw end so I always flatten them after reed mounting. If the reed shoe fit before you cleaned it up, flattening with s file will make it thin enough to need to slide farther forward in the dovetail and you may not have room to move it forward and will need to shim. Given that dovetail mounted reeds will seal on their side edges. As long as they are touching at the tip and base end, there isn’t much place for the air to get in. Yours seems to be ok at those locations.
  • Create New...