conzertino Posted August 3, 2009 Share Posted August 3, 2009 I'm still looking for the pressure inside a concertina while played. I need the value to buy the right pressure-sensor for a MIDI-project. I used an electric air-pump for tuning many years ago with a water-tube pressure-gauge. If I remember rightly, I was using about 40cm of water-hight equivalent to 4 mbar - not a lot really!?! Any ideas or experiences??? Link to comment Share on other sites More sharing options...
Chris Ghent Posted August 4, 2009 Share Posted August 4, 2009 I'm still looking for the pressure inside a concertina while played. I need the value to buy the right pressure-sensor for a MIDI-project. I used an electric air-pump for tuning many years ago with a water-tube pressure-gauge. If I remember rightly, I was using about 40cm of water-hight equivalent to 4 mbar - not a lot really!?! Any ideas or experiences??? I'm running a constant vacuum of 1.6" water pressure in my tuning rig but would like to know what happens inside a concertina myself. The only way to practically find out would be to attach a nipple to a concertina and lead it to a magnehelic gauge. However I'm sure someone out there must have the maths to be able to calculate it. The area of the underside of the action box times the force applied will lead somehow to a psi or whatever the metric equivalent is (I live in a metric country but have never managed to convert pressure and nor has anyone else, tyre gauges are still calibrated in psi). Any maths people out there? I would call for a maths whiz but I suspect it is very easy... The answer may be complicated by the flexibility of the reeds and the clearances. A Stagi played loud will be using much higher pressures than a Dipper at the same volume. Chris Link to comment Share on other sites More sharing options...
Johann Posted August 4, 2009 Share Posted August 4, 2009 With accordions we just put in a very thin needle pipe into a bellows nail whole, to see how strong the air pressure is. Pipe is attached to the water U pipe gauge, easel self constructed, or a other pressure manometer. Johann Link to comment Share on other sites More sharing options...
conzertino Posted August 4, 2009 Author Share Posted August 4, 2009 !,5" of water makes more sense! I did the maths last night: 1 Pascal ( Pa ) = 1 Newton ( N ) / m2 100 Pascal = 1 mbar or 1 cm of water Assuming an applied pressure of 10 Newton to an area of 15 X 15 cm ( one concertina-end ) gives 4 mbar, which makes sense ( see above ). Heavy playing of a small concertina could bring the pressure to 10 mbar or more. I ordered a 25 mbar pressure-sensor! Link to comment Share on other sites More sharing options...
Alan Day Posted August 4, 2009 Share Posted August 4, 2009 Interesting experiment .It obviously depends on how loud you are playing. To get the psi I would pop down to the local Tyre repair shop.Get an old inner tube of a large diameter.cut off one end near the valve and make it airtight and fix the other end over the end of the concertina bellows,again making it airtight. Blow up the tube until you can get a reading on the tyre pressure gauge and then see what it goes up to when forcing air through the bellows. Take one reading from the other and you have the answer. Al Link to comment Share on other sites More sharing options...
TomB-R Posted August 4, 2009 Share Posted August 4, 2009 Interesting experiment .It obviously depends on how loud you are playing. To get the psi I would pop down to the local Tyre repair shop.Get an old inner tube of a large diameter.cut off one end near the valve and make it airtight and fix the other end over the end of the concertina bellows,again making it airtight. Blow up the tube until you can get a reading on the tyre pressure gauge and then see what it goes up to when forcing air through the bellows. Take one reading from the other and you have the answer.Al Eek! You do know Alan is joking don't you folks! 4mbar is a bit less than 1oz per square inch! (By my reckoning) Link to comment Share on other sites More sharing options...
Jack Bradshaw Posted August 4, 2009 Share Posted August 4, 2009 Interesting experiment .It obviously depends on how loud you are playing. To get the psi I would pop down to the local Tyre repair shop.Get an old inner tube of a large diameter.cut off one end near the valve and make it airtight and fix the other end over the end of the concertina bellows,again making it airtight. Blow up the tube until you can get a reading on the tyre pressure gauge and then see what it goes up to when forcing air through the bellows. Take one reading from the other and you have the answer.Al Eek! You do know Alan is joking don't you folks! 4mbar is a bit less than 1oz per square inch! (By my reckoning) We know Alan is joking...but does Alan know Alan is joking ? Link to comment Share on other sites More sharing options...
Alan Day Posted August 4, 2009 Share Posted August 4, 2009 Interesting experiment .It obviously depends on how loud you are playing. To get the psi I would pop down to the local Tyre repair shop.Get an old inner tube of a large diameter.cut off one end near the valve and make it airtight and fix the other end over the end of the concertina bellows,again making it airtight. Blow up the tube until you can get a reading on the tyre pressure gauge and then see what it goes up to when forcing air through the bellows. Take one reading from the other and you have the answer.Al Eek! You do know Alan is joking don't you folks! 4mbar is a bit less than 1oz per square inch! (By my reckoning) We know Alan is joking...but does Alan know Alan is joking ? Well no, but Iv'e had to cancel the patent!! Back to the drawing board then. Al Link to comment Share on other sites More sharing options...
ragtimer Posted August 7, 2009 Share Posted August 7, 2009 Eek! You do know Alan is joking don't you folks! 4mbar is a bit less than 1oz per square inch! (By my reckoning) Actually, 1 oz/sq in is over 1 inch of water, which is more than enough to paly free reeds at a soft to medium volume. It's almost 27 inches of water to a psi. However, it would take more liek 40 mbar, not 4, to equal slightly over 1" of water. FWIW, when I was trying to set reeds on my Bastari bandoneon, I got the good ones to speak at about 1/3", while the tough ones took more liek 2/3", as measured on a Magnehelic guage. (Someone mentioned those gauges, and they are the best!). --Mike K. Link to comment Share on other sites More sharing options...
Chris Ghent Posted August 8, 2009 Share Posted August 8, 2009 [FWIW, when I was trying to set reeds on my Bastari bandoneon, I got the good ones to speak at about 1/3", while the tough ones took more liek 2/3", as measured on a Magnehelic guage. (Someone mentioned those gauges, and they are the best!). I like it if reeds speak in the .1 to .3" range (you need a .5" max dial to make it readable) but speaking pressure as read on the magnehelic is not as simple as, ~low reading GOOD, high reading BAD~ ie. a reed which will choke will likely read low. A lower reed will naturally start at a much lower pressure (actually "vacuum") than a high reed, so a high reed at .3 might work well in a set with a bass reed at .12"... Chris Link to comment Share on other sites More sharing options...
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