Button pressure on CBA's ?

[Geoff de Limousin]

I am wondering what are your preferences for button keyboard pressure ?

On my two favorite CBA's there is a lot of difference between each instrument. I am measuring 50g to start moving the buttons on one of them and 100g on the other. The more recently 'professionally renovated' instrument is the lighter of the two and thus I might imagine this represents a modern norme that is made possible due to replacement of all the pallets. The much heavier return spring set up on my 'home renovated ' box is due to my attempts to get an equal pressure thoughout the range whilst alieviating some air loss due to very old pallets.

It is the difference of 'feel' between the two that is a cause for concern. For best control perhaps one should only play THE instrument because the sense of touch, reaction of notes and control of tone is never exactly the same on each ... but....

I use a simple device for testing button pressure; a hand held dial gauge used for setting Relay springs and the like.

 

[losthobos]

Interesting...though I've no gauge or ideas of actual pressure but my old Ranco Guglielmo was light as a whisper on the buttons but had a lit of clatter / mechanical noise..
My older Piermaria is not quite as light but I think it makes my playing sound like I've had half a bottle of wine and I a little slurred
My Brandoni kingline had a heavier action but with superb craftmanship had very little mechanical noise to worry about...but didn't like the action ...found it as heavy as the reeds bark..
My modernish SEM sits happily in between and has a lighter action and little mech noise...
Now off to try Goldilocks porridge <EMOJI seq="1f609">?</EMOJI>

 

[george garside]

its not just button pressure on CBA's but the question is just as relevant to British Chromatics, piano boxes and indeed small melodeons.
My take on the matter is simply that no conscious effort should be required to press a button or key. The fingers should rest very lightly on the buttons and certainly not hard enough to accidentally press them. The job of the springs is not to support the fingers but to instantly cut off the sound by immediately closing the pallet when a button is released.

the buttons do not in any way regulate the volume/dynamics and are merely on /off switches. Good bellows control is at the heart good dynamics

george

 

[debra]

I have no gauge to measure the pressure on my accordions. But... the levers must be different for each row, which is typically compensated by the placement of the pallets. The first row has the longest lever but the pallets are also furthest away from your body so a stronger spring is needed to keep the pallet closed than for the third row which has the shorter levers but the pallets are closest to your body and thus shorter too. The real challenge on a CBA is to have a reasonable pressure for the 4rd and 5th row.
on a PA it is similar: the white keys have a longer lever but use the row of pallets furthest away and the black keys have shorter levers and the pallets closer by. (But there is often an exception as there are more white than black keys so one or a few white keys do go to the closer pallets. I think it is actually common to have this for the highest E on a 41 key keyboard.)
Keeping the pressure even between rows is more important than what the average pressure level is.

 

[Deleted member 48]

The pressure of the buttons, the even pressure between the rows, and I would also take into consideration the response level for the vibration of the reeds depending on the valves opening degree.

Reminds me a bit of a 2007 patent by a Steirisch Harmonika maker (Haglmo Harmonikas), a physicist, who patented a new 4 axes system for Steirisch Harmonika:
http://www.faz.net/aktuell/technik-...88558.html?printPagedArticle=true#pageIndex_2
Vier Achsen für den perfekten Luftstrom (Four Axes for the perfect air stream)

This is for something different, a bisonoric Steirisch Harmonika, but maybe a similar system was or can be used in the world of CBAs or PAs (?).
Being a physicist, I suppose he did some very precise calculations on button pressure and air flow for this patent.

 

[Deleted member 48]

For those who are interested in reading the patent about the 4 axes system, it is here:
http://www.google.com/patents/EP1909259A2?cl=en
EP 1909259 A2

The Haglmo 4 axes mechanics is shown on the website:
http://www.haglmo-harmonika.de/diskantmechanik.php
Diese exklusive Diskantmechanik der HAGLMO Instrumente schafft durch exakte Angleichung der Hebellängen über alle vier Reihen hinweg ein völlig identisches Spielgefühl der vier Reihen bei optimaler Verkürzung aller Hebellängen. Diese einzigartige Bauweise bietet ein außergewöhnlich direktes Spielgefühl der gesamten Diskanttastatur. So erreichen wir für Sie höchste Ergonomie für Ihre Spielhand.

http://www.haglmo-harmonika.de/technik.php
Die unterschiedlich langen Hebel der verschiedener Tastenreihen bisheriger Diskantmechaniken wurden beseitigt und eine Hebelmechanik entwickelt, die ausschließlich gleich lange Hebel bei gleichzeitiger Minimierung der Hebellängen besitzt. Damit wurde die Ergonomie der Diskanttastatur wesentlich verbessert. Für eine günstige Spielhaltung der Hand ist bei uns der Griffstock stärker zum Körper hin geneigt, gleichzeitig ist der Griffstock aber etwas am nach vorn versetzt, um die Ellenbeuge beim Spiel zu entlasten. Diese optimale Lage des Griffstockes ist nur in Kombination mit unserer Diskantmechanik möglich.

 

[debra]

I won't pretend to understand all the intricacies of that patent, except that it ensures all levers have the same length. That helps to guarantee identical behavior of the 4 rows of buttons, but it makes it harder to produce the same tone (timbre) for all rows, hence the strange arch over one of the rows of pallets. Producing the same timbre for all reed blocks is something that has kept manufacturers/designers busy for decades and is still an unsolved problem. One of the most striking examples of the problem is the metal cap over the top row of pallets in the Hohner Atlantic IV N which tries to compensate for the pallets at the other end being obscured by the solid part of the grille and the register mechanism. Designers are also trying to equalize the timbre of different reed blocks in the cassotto and of the different bass reed blocks. There are partial results at best. The best equalized timbre I heard so far was from the Beltuna Prestige Paris IV, a CBA with 58 notes and no timbre difference between the rows. Unfortunately this CBA has a large timbre difference between the lowest bass reed block and all higher notes. In accordions with 2 reed blocks in cassotto the problem isn't very large but accordions with 3 reed blocks in cassotto really suffer from the 3rd row of buttons (reed block closest to the "exit" of the cassotto) sounding different from the other two blocks that are deeper in the cassotto.
But we digress here... from making the buttons "feel" the same way to making the rows of buttons also produce the same timbre...