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Evan

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Hey! In my pursuit of a bandoneon, I found a used accordion at an Estate Sale and bought it!

I have several questions that I couldn't find answers to a search of prior threads. If there are threads on any of these topics, please direct me to them. Thank you!

Accordion: Carlo Robelli, 120 button, piano accordion, two reed boxes (per side), push and pull tone the same on both side. "MADE IN ITALY, SER 59334"

Q1: Can anyone direct me to where I might be able to tell the year that this accordion was made? By the look of its carrier case, I'd guess in the 70's. But I'm wondering if there are places where the serial number can be used to learn more about this specific accordion.

Q2: I'd like to replace the back pad / bellow pad. The one that was on there disintegrated. Red sand everywhere... Anyone have favored online retail stores for these types of items? (And are they all the same size for 120's?) I probably will want to buy new shoulder straps too eventually.

Q3: I'd like to get more familiar with the exact chord structure for each of the Bass buttons. Is there a diagram anywhere that labels the buttons, AND provides the musical notes on a treble and bass staff for each button? I can find a button diagram by itself with a Google search. And I understand the basic button arrangement. (3rd, root, M, m, 7th, D). What I am lacking is a staff with the chord notes listed. So I thought a combo diagram plus musical staff would be helpful.

Q4: I think I will want to do some tuning on it myself at some point so...
a) Anyone know of where I can buy an air box for that? Ie. A bellow with air plate on top to put the reed boxes on to test and tune individual reeds. Something like this: Or do people usually just end up having to make those themselves? Any other "out of the accordion" reed testing methods are welcome. So far I've just used my own breath, but that doesn't seem the best.
And.. b) Anyone know how much one can change a reed's pitch by grinding it with a Dremel before the reed is damaged beyond function? I may want to change pitch by several Hertz.

Thanks for any input you can provide! Evan
 
Hi Evan 🙂👍
For searching the forum regarding your questions, use "stradella bass system", "stradella bass layout", and "circle of fifths" in the search engine (also on the web generally).
Also, relating to your particular accordion, send us some nice clear pictures! 🙂
 
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Contrary to what the name of a "tuning table" (what you call and "air box") suggests, such a rig is ONLY usable to TEST reeds (check whether they play well, adjust voicing, check leathers) and NOT usable to do tuning. You can only check the tuning with the reed blocks inside the accordion. Adjusting the tuning by filing or scratching can be done with the blocks inside the accordion but is easier when you take the reed blocks out. Don't forget to *always* support the reed you are going to file or scratch so as to not bend it.
 
Thank you colinm and debra. Those both seem like helpful contributions.

Debra, I had wondered if having the reed boxes inside the accordion would make a difference. Thank you for helping confirm that it would. To clarify, are you indicating that if I were to tune a reed on a tuning table to 440 Hz, that in the accordion it would / could be 440 +/- something, but not exactly 440? I'm also wondering, if so, then does tuning the inner reeds typically mean taking the reed box out for the filing / scratching, then putting them back in to check their frequency? That would seem fairly laborious! lol Is there a special tool for that besides a very small Dremel tip?

Thank you both for correcting the terminology re the tuning table. Still learning the accordion jargon.
 
The way I do tuning is to measure the frequencies with the reeds in the accordion and then I've got a spreadsheet that calculates how much each reed needs tuning (up or down in cents). I've got the spreadsheet to map the values into a diagram of the reed blocks so it's easier to see what I'm tuning.
Then you take a block out and adjust the reeds up or down the amount indicated in cents - not an absolute amount. When it goes back in the accordion it should be about the right frequency. This usually takes about 3 tries due to overshoot etc.
With the blocks out I use a wooden box with a foot pump attached to sound the reeds and a phone app to measure the cents.

It takes time to get the tuning right but it does work eventually.

Spreadsheets are very handy for tuning (this was generated from columns of measured frequencies):

2022-04-28_200615.png
 
Thanks Glug. Nice spreadsheet. I figured I would use one as well when I got to that point. I like how you designed it to match the reed blocks. Seems very practical.

Can you advise me, in a relative nutshell, why you prefer the cents method over absolute frequencies? And do you have a particular phone app that you like for measuring those changes?

And you're welcome Dingo40. Any idea of time period this particular accordion may have come from?
 
well if no-one else will say it...

one should only use a Dremel tool in the vicinity of an accordion reed
to possibly hold a nice diamond dust tip for HAND motion use only

i mean don"t ever turn it on

use it only as a pin vise

never

ever

put the battery in

period

nope

not a good idea
 
Evan,
Any idea of time period this particular accordion may have come from?
In my opinion, probably the early to mid 1950s🙂
 
Thank you colinm and debra. Those both seem like helpful contributions.

Debra, I had wondered if having the reed boxes inside the accordion would make a difference. Thank you for helping confirm that it would. To clarify, are you indicating that if I were to tune a reed on a tuning table to 440 Hz, that in the accordion it would / could be 440 +/- something, but not exactly 440? I'm also wondering, if so, then does tuning the inner reeds typically mean taking the reed box out for the filing / scratching, then putting them back in to check their frequency? That would seem fairly laborious! lol Is there a special tool for that besides a very small Dremel tip?

Thank you both for correcting the terminology re the tuning table. Still learning the accordion jargon.
The main problem with tuning outside the accordion is that each note may have a different deviation between inside and outside the accordion, so the end result will simply sound like an accordion that is out of tune, not one that is in tune at a slightly different frequency. So you need to follow Glug's method. You can also just make adjustments you think are close (based on the table), and then measure everything inside the accordion again. After 4 or 5 rounds of doing so you will reach a perfect result.
Note that an accordion will sound fine if all the reeds on the low end are within 1 cent of each other and of the target, and at the high end within 0.5 cent of each other and of the target. You should not try to reach 0.0 cents on all notes because even if you do changing temperature will mean the accordion may easily go off by 0.5 cent in just a few hours.
 
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A good tuning app is APTuner. It is available on Windows and iOS. I think he is working on an Android version. There is no advertising or in-app purchases.

https://www.bromsaudio.com/

The attached file "italian_hook.pdf" is a drawing I made of the hook I use to access inside reeds. I tried several different shapes and sizes of hooks and this one worked the best. I made it from 13-gauge music wire just because that is what I had in the basement. Other wire can be used. The music wire is tempered spring steel so it has some flexibility. I haven't tried stiffer wire that has no "give" to it.
 

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