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Author Topic: Tuning table problem.  (Read 696 times)

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Frankola

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Tuning table problem.
« on: August 21, 2019, 04:25:50 PM »

Greetings from Norway,and thank you for a great forum. This is my first post and my english may not be the best. I have a problem with my tuning desk/table. It is a simple construction,with a bellow attached under the desk with a hole in the plate,letting the air inn. The tableplate is made of plywood/cardboard and is ca. 5 cm thick,with a 12 mm pipe to let the air inn. The issue is that the pitch seems to be lower than it actually is and it is not consistant either, therefore it is difficult to  get even results. Can it be the thickness of the tableplate that is messing with me and my measurements? 
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mselic

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Re: Tuning table problem.
« Reply #1 on: August 21, 2019, 04:33:56 PM »

Others will no doubt be along to elaborate, but the pitch will always be different when you are tuning reedblocks outside of the instrument. Final tuning must always take place with the blocks IN the instrument, and ideally using its own bellows.
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Theo

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Re: Tuning table problem.
« Reply #2 on: August 21, 2019, 04:46:29 PM »

Can you post a photo please? 

When you design a tuning bellows it helps to make the the air holes the same size as the air holes in a typical accordion.  The top panel should be about the same thickness too, so 5cm is much too thick.  It would be better to make it about 5mm.  You will find that will make the pitch on the tuning table much closer to the pitch inside the accordion.
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Theo Gibb - Gateshead UK

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malcolmbebb

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Re: Tuning table problem.
« Reply #3 on: August 21, 2019, 05:37:32 PM »

Following Theo's post above, the thickness of my tuning table top was originally about 20mm and there was always a big offset. I cut the middle section out and replaced it with 5mm plywood, and it's now much closer to the instrument.
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Frankola

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Re: Tuning table problem.
« Reply #4 on: August 21, 2019, 08:31:44 PM »

I know that it is difference in and out of the box, but the measurments was so uneven,therefore no pattern to follow. I think I will start building a new tuning table,to get more exact tunings .

Thank you for your answers
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Jon Stapleton

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Re: Tuning table problem.
« Reply #5 on: August 21, 2019, 10:38:28 PM »

I know this has been said before but .  Yes make your tuning table as similar as you can to the box you want to work on.    If your tuning table is close enough physically to the actual box, you can tune close enough that you will only need minor adjustments inside the actual box itself. It is worth making the effort.  But different sets of reeds have different offsets even from the same type of box and on the same tuning table EVEN in the same key,  they just behave differently because they are all slightly different.  The best modification i made to my table was as per Malcombebbs comment . i.e i used a bit of ply from an old PA of the same thickness and density as the boxes i tend to work on, but even so the minimum correction i have to make is usually about 2cents at A4  and the further up and down the scale the less predictable the required adjustment becomes.  It took me a long time to understand that the oft quoted mantra about tuning inside the box was right.  I spent a long time trying to make the perfect tuning table .  I only gave up because during that time period i had finally started to get the hang of final tuning in the box itself!  This is where your effort is best directed.   Practice makes perfect as we say in blighty (in my case better if not perfect)
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