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Chris Ghent

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About Chris Ghent

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    Heavyweight Boxer

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    http://www.concertina.com.au
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    Blue Mountains NSW

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  1. Sean, good question. It is best to keep the concertina lightly compressed when not using it. If you do not do this then the bellows will become less willing to close fully. This can be an issue when you need that last little bit of air on the push. I have seen one Morse Ceili (no reflection on Morse Ceilis, terrific instruments, most concertinas will act the same) which was unable to close the last 1” (25mm) without increasing pressure to compensate for the open resting position that had come about because the owner had never put it back in the case. After a number of years of being constantly held closed the bellows will give up and stay closed. If your case does not have blocks to hold the bellows closed, then fit them. If you want to keep the concertina out ready to play (I do) I endorse the idea of a velcro ended strip to hold the bellows closed, or make a wooden frame to pop the concertina into (I did) which keeps the concertina on show and means it just needs to be picked up to be played. The valves on accordions are not on the same angle as concertina valves, depending on the accordion, and may not be as affected by the accordion sitting vertically.
  2. If you choose a typical reed and take its valve off and reassemble the concertina you will find out whether it is the valves or not. If that note jumps out then a lighter valve will help.
  3. Lachenals often have reeds which are neither loud nor fast and without a high quality reed to compare you might have trouble assessing performance on the tuning rig.
  4. There can be further complications, but if the heat method does not work, grind the head of the screw off, lift the action box off the screw, if the screw still won’t come out replace the screw and the captive nut.
  5. Hi Tom, I expected rounded surfaces to be quieter in the higher freqs because of a couple of misspent but enjoyable years hangliding in the middle 70s. You develop a sense of the way wind moves around structures, what creates turbulence and also the noise made by different shapes. I never thought the rounded surfaces would lower volume because I equated volume with quantity of airflow and the nature of the sides of the clearance would not change that; as long as the clearance was the same I thought the volume would be. The perceived volume dropped because the higher partials now removed were discordant ones. I have long thought (and some of your words are the first confirming ones I've read) that a reed will give best speed and volume when, as it moves down to the top of the slot, the entire slot is blocked off as much as possible at the same time. I create this effect by bending the set into the reed in exactly the place it will bend down under pressure. For this reason the simple, "adjust the reed until the tip is around its own thickness above the frame" is not just simple but simplistic. At the moment at which the reed lies perfectly flat at the top of the slot I think there is an instant of air compression (this, I think, is your water hammer moment, though water cannot compress) followed by an explosion of air expansion as the reed moves down. (An aside, in the 70s I had a motorcycle tuning book called "Tuning for Speed", worth hundreds now, wish I could find it, and in it Phil Irving, designer of the Vincent, says, "compression is acceleration"). I don't see any reason why this would be lessened by rounded surfaces rather then square if the frame/tongue clearance is the same. When I find the reeds (I made two), I will see if I can find a volume comparison but there would be many obstacles to a clean comparison with a square edged reed. I never really did think the rounded edges in the frame and tongue might make the reed double action but as you say, worth a few seconds experiment. What I did think might work was creating a sinusoidal shape to the tongue. If the sides of the frame were similar top and bottom ) ( and the reed snaked under the tight spot and then above it then the conditions might exist to start both ways. The downsides might be a lack of a definite compression point as above and slower starting when the part of the reed above the frame was at the root end of the tongue. I have also been thinking of those harmonium reeds in which the last 5 mms are twisted to a 45° angle. These might start both ways. Of course the inefficiency of such a reed only makes sense in the light of a large wind chest and a pair of pedals but just to check the principle it might be interesting. To recap, I think we might be in agreement on the form of the slot except for whether the nature of the compression point (square or rounded) might affect the volume in any way other than increased or decreased by the addition or subtraction of higher harmonics. I am always conscious Tom, your words might have a more precise meaning than mine in scientific terms so my apologies if I have misunderstood anything you have said. For my own errors I am, of course, sorry.
  6. Some time ago I set a reed down into the frame by .75mm so I could create a rounded compression point on the frame rather than using the sharp top edge. The tongue was rounded on the edge also. The intention was to remove the higher partials I theorised were produced by the sharp edges. It worked, the higher partials were noticeably absent on the bench. In the concertina there was no appreciable difference and I surmised the structure of the concertina was filtering them out to roughly the same degree. More recently I have read of “bombate” accordion reeds which have rounded tongues for the same reason. The mirrored frame shape above and below the reed did not suggest it might start in either direction, mind you I never tried. The reed is around somewhere, I’ll set the tongue to a neutral position next time it surfaces and see if the shape lets it start both ways. Not holding my breath.
  7. Reeds are directional because the reed tongue needs to be raised into the airstream slightly when at rest in order to create a starting sequence. I have wondered recently whether a reed shaped like a gentle sine wave, and thus having part below the tightest part of the slot and also part above, might be induced to start both ways. There would be an efficiency penalty and a slightly different tone and the geometry of the reed slot might need adjustment.
  8. Is there any chance the button is slowing due to friction from the end bushing? Humidity can cause the bushing to swell. And when you take the spring off and rock the lever by hand is it smooth? Is there any chance the lever has bent sideways slightly so the button has a side load. To check this, make sure any sideways wobble in the button travels through the vertical point. Another way to check is put the end back on, put a few bolts through to make sure it is aligned, and then lift it off as vertically as possible and examine the button to see if it is straight. The replacement spring, is it adjusted to be strong enough? Increasing the preload to see if the problem is resolved can provide a good clue. Is the seat absolutely clean? The push/pull imbalance in sealing can overcome small seal issues on the pull.
  9. Don't know who invented it but Dana Johnson of Kensington Concertinas has been using this system as long as I can remember. It works very well.
  10. Don’t give up on the reeds; clean them and de-rust them.
  11. Stiffness is a known side effect of folded strips, which were introduced when the industry was in financial strife as a way to cut costs rather than a way to raise standards. I have used three different glues with no change in bellows stiffness.
  12. Seth, when you say “cards only” in the second set, what did you use in the first set?
  13. Well done, there is still time to run before it takes over your life... Not sure I would accept the change of glue as a primary reason for the bellows being less stiff. It sometimes depends where you put it. And often when people say their bellows are stiff it is inefficient reeds to blame.
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