11 folds bellows

[Mikefule]

The air pressure generated by the bellows affects the attack and volume of the reeds.

 

Pressure and volume are inversely related: on the push, in order to double the pressure, you must halve the volume of the bellows.  On the pull, if you want to double the pressure, you must double the volume of the bellows.  (This is approximate as there are other allowances that need to be made.)

 

Thus, if you use the full length available in a set of longer bellows, you have to move the ends further in the same amount of time (i.e. faster!) to achieve the same change in pressure.

 

Therefore, with longer bellows, if you want to play with the same attack and volume as you did with the shorter bellows, you will need to move your hands further and faster.

 

Especially if you are switching from push to pull or vice versa, then I can imagine that the effect is very noticeable.

[wunks]

2 hours ago, Mikefule said:

The air pressure generated by the bellows affects the attack and volume of the reeds.

 

Pressure and volume are inversely related: on the push, in order to double the pressure, you must halve the volume of the bellows.  On the pull, if you want to double the pressure, you must double the volume of the bellows.  (This is approximate as there are other allowances that need to be made.)

 

Thus, if you use the full length available in a set of longer bellows, you have to move the ends further in the same amount of time (i.e. faster!) to achieve the same change in pressure.

 

Therefore, with longer bellows, if you want to play with the same attack and volume as you did with the shorter bellows, you will need to move your hands further and faster.

 

Especially if you are switching from push to pull or vice versa, then I can imagine that the effect is very noticeable.

Perhaps related to this, I have two duets, one larger with thin tight bellows folds(7) the other a 6 1/4" with (6) thick sturdy folds.  When at rest on a table the former remains tight as from its blocked case.  The latter will expand of it's own about 1".  I would call the one neutral, the other springy.  I don't think about it but when I play the big box I play longer phrases in either direction and faster tunes are more difficult ( both boxes have basically the same notes).  Playing the small one I find myself playing with the bellows in a very closed position with the instrument "playing it's self" to some extent on the draw providing a much quicker response.