Pre-tuning of reeds?

[pitzelberger]

Dear forum, I like to teach myself how to repair accordions and hence have bought an old out of tune box only for the purpose of disassembling and assembling it back again. Currently I have removed all the reads and cleaned them. Now, before attaching new valves to them and waxing them back, I was wondering whether it makes sense to do some kind of pre-tuning? I have build a tuning bellows and some wooden blocks to make them sound, similar to the ones in this video. I know that their tuning will change when I install them back, but nevertheless, as they seem to be quite out of tune (+/- 15 cent sometimes even on the same reed when pushing or pulling) I was wondering whether it makes sense to pre-tune them now, so that I have to do later less filing while the valves and reed-block are in my way? My idea was to tune them all to approximately 0 cent now, install them back into the accordion and then do the further adjustments. Is this a valid approach, or do I have to expect the tuning changes after reinstalling them to be so large and unpredictable that all the filing I do now only means additional wear to the reeds but nothing I can benefit from during the later fine-tuning?

 

[debra]

Pre-tuning only makes sense if you have a good idea about the difference between the tuning of these specific reeds on the reed block versus in the accordion. Accordion makers produce series of identical accordions. They have a list of deviations of the reeds outside of the accordion (maybe even before waxing them in) versus inside the accordion. As a result they can safely pre-tune and then know the deviations inside the accordion will be small so that final tuning can be done relatively quickly. This whole process cannot be done for a "one of a kind" job.

 

[knobby]

the difference between the tuning of these specific reeds on the reed block versus in the accordion.

How much difference would this normally be, roughly speaking?

 

[debra]

How much difference would this normally be, roughly speaking?

It varies widely... Reeds will drop around 10 cents when a valve is added. Reeds can also go up or down about 5 cents when placed on a reed block and about the same when that reed block is placed in the accordion. The difference between measuring a reed on the reed block and in the accordion can be 5 cents, and can be higher or lower... So really a table of the deviations is needed in order to do pre-tuning, and this can only be done and only makes sense for a factory that makes series of identical accordions.
For "pitzelberger" it's too late, but a form of pre-tuning that is possible in accordion repair is to start by measuring the tuning, writing everything down in a table (writing down the deviations in cents). Then, when the reeds are off you can measure the tuning of a reed and then do "pre-tuning" to correct the deviation written down in the table. When you have done all that and put the accordion back together, the corrections you applied should reduce the deviation in the accordion to maybe 2 or 3 cents. This makes the final tuning easier than without pre-tuning.

 

[Ventura]

and so many sheets of notepaper with these painstakingly written down cents
deviations, and so much time spent it hurts my head just remembering

and this is why tuning takes such infinite patience as well as skill which
i barely have enough to do my own accordions much less someone elses !

a toast to the professional Tuners in our midst !

peppermint Schnapps, perhaps ?

 

[knobby]

a form of pre-tuning that is possible in accordion repair is to start by measuring the tuning, writing everything down in a table (writing down the deviations in cents). Then, when the reeds are off you can measure the tuning of a reed and then do "pre-tuning" to correct the deviation written down in the table.

I take it that to do this you must first do any other work required on the reeds, e.g. replace valves, before taking your initial measurements with the reeds in the accordion? Then you would remove the reed blocks again to do your "pre-tuning"?

 

[Ventura]

well, you can tune all the reeds to their baseline model, even bare with no leathers
(after the reed tongues have been cleaned and wiped)
you need to make yourself a small embochure to set the bare reeds in, with a slider
as reeds vary in length

but if you measure all the reeds on your tuning bench, and set your tuner to
the average median (most tuners can be set variably 440, 441, 442, etc)
then pre-tune each reed to "Center" your entire set of reeds will be tuned to themselves
fairly well

after you have rebuilt all the valves and waxed them in, you go from there

 

[Dingo40]

My head's spinning.
All I can say is, I sat in on several sessions of resuscitating my ancient $20-00 I. Busilacchio 3 voiced PA, which had everything wrong with it, including missing, broken and rusted shut reeds.
My technician took them off the blocks, one by one, tuned them up on a set of foot operated bellows with dremmel and tuner, revalved them, rewaxed them back on the block and shoved them back in the accordion.
He did this at the rate of eight to ten (double) reeds per hour, while enjoying cups of tea and biscuits and carrying on a lively conversation about everything under the sun!
That was at least 35 years ago, and this particular accordion has been fine ever since except for some occasional spot tuning of the F# above middle C. I still play it frequently ?.
There was no tuning "in the accordion ".
Just lucky, I guess??

 

[Ventura]

if an accordion is only played "solo" it only needs to
be in tune with itself, as my friend Faithe used to frequently preach

 

[Dingo40]

Actually, I did play it quite a lot in a group at our fortnightly accordion group meetings, and at a folk group (where you couldn't really hear anyone for the ambient noise) and I never noticed it "clashing" with the neighbours ?
(Played it today: octaves sound great, left and right hand chords coincide, all individual notes sound right! Compression is excellent! This old accordion is at least 70 years old !??)

 

[debra]

I take it that to do this you must first do any other work required on the reeds, e.g. replace valves, before taking your initial measurements with the reeds in the accordion? Then you would remove the reed blocks again to do your "pre-tuning"?

That is correct: all the work an accordion needs besides tuning needs to be done before you take "initial" measurements.

 

[Tom]

Omg, I've started to notice out of tune reeds on my "new" (less than 5 year old) accordion. I have never tuned a reed and have had less than spectacular luck with "professionals." Guess I'll have to figure it out.....

 

[TomBR]

Given that your objective is to learn about tuning etc, and given that some of your reeds are quite out of tune I would say pre-tuning is worthwhile experience, but don't try to be too precise, adjust the ones that are more than 4 or 5 cents out.
You'll learn about tuning, you can get all your reeds speaking well and "happily", then install them and do your fine tuning.

 

[pitzelberger]

Nice to see that my post finally resulted in a larger discussion. Let me take this as a chance to report a bit on my progress.

I have to agree with Ventura that this is painstaking work. I finally managed to restore and tune the treble side, but it took me many weekends and the Christmas break to arrive there. Of course, I was particularly slow as this was the first time I did everything and I also had to repeat some of the steps, e.g. waxing and tuning, several times until I arrived at OK results.

Following debra's advice, I did not try to pretune the reeds before waxing them back to the blocks. I don’t think this would have made much sense as the accordion's condition was quite bad in the beginning (some reeds were stuck, leathers falling off etc.), so that I could not record valid cent deviations in the beginning.

After waxing and replacing the leathers, I then went for the approach where I calculated cent deviation twice, i.e. once with the reed block inside and once with the reed block outside of the accordion. What was really helpful for this, was a kind of sophisticated excel sheet that I set up, which allowed me to calculate the target cent deviations that I have to achieve outside, so that the inside deviations become zeros. Also a tuning software, which allowed me to first record all the frequencies and then simply copy-paste them into excel was really helpful.

I have attached some example plots that I have done in excel which show how much inside tuning differed from outside tuning.


Nevertheless, even with this approach, I learned that I have to do another fine tuning, with the reeds back in the accordion so that I can get all the reeds deviation within +/- 1 cent. With time, I lost my fear of this approach and learned that it is not so hard to tune reeds while in the accordion. Especially after I learned how to use the reed hook properly. The accordion is only a 32 bass and not so heavy, so I could test each reed individually on the accordion's bellows, lift the treble, turn it and tune the reed easily, but I can imagine that this becomes more difficult with a more heavy full size accordion. Also as it is an old box, I didn’t have to worry much about putting some scratches to the grill or similar damage while having it turned around and doing the tuning. As I do not have a dedicated tuning beelow for this kind of tuning, I was simply using the accordions below. I would be interested in the others' experience, whether you can do some damage to the bellow’s frame if you repeat this step too often?

One thing that was particularly annoying with this accordion, was that there are no individual registers for all the reeds, it only has a M, MM, and LMM switch. So while tuning the L for instance, I had to block off the other reeds. This was particularly difficult when I then tried to get the octave clean between L and M, where I constantly had to block the M on and off.

Nevertheless, in the end I arrived at a result, which sounds OK to me and I have now more confidence of doing some tuning on my more expensive accordions. At the moment I am still working on waxing and tuning the bass side of this accordion. Overall with the limited time I have it might take me almost half a year to get this job completely done. That's OK for me, as I did it out of interest and fun, but it also showed me what is the value of this work when done by a professional.

 

[boxplayer4000]

In the video at the head of this thread it's not clear how the air flow is being generated. I suspect he's using his feet to power a set of bellows.
Bellows are preferable to a mechanical constant flow system as they allow the tuner to better 'feel' the response of the reed. Also the tuner in
this video might just have used wooden reed blocks to hold the reeds while he's blowing them and saved a lot of work making all the small wooden supports. See online videos of the Hohner tuner.

 

[oldbayan]

I bought a few sets of Cagnoni reeds from CGM, they were "pre-tuned" so it helped to figure out the fine tuning once they were mounted on the blocks inside the accordions as they had a consistent starting point.