aftertouch

[Delwin D Fandrich]

Roger Jolly wrote:

> Greetings Del,
>     A great post, in my travels I find that jack positioning (front to rear)
> and jack hieght is a frequently omited, and misunderstood part of the
> regulation.

It's also misunderstood by some action designers who simply don't leave enough room
between those ridiculous jack letoff dowels to get at the adjustment screws. I've had
several "technicians" tell me that those screws were pre-set at the factory and were not
supposed to be tampered with in the field.


>     For special performers I will push the the let off and drop to almost
> 1/32" with 10 to 15 thou of after touch. These specs feel great to the
> performers but will not stand wide or prolonged humidity swings. The action
> must also be in first class mechanical condition.

It also helps to have firm felts and leathers. I think action manufacturers get too
carried away with the notion of ensuring absolutely silent actions. The only way to
achieve this is to use felts and leathers that are too soft for snappy action performance.
This is especially true with capstan felts, jack letoff punchings, hammershank knuckles
and center and front rail felt key punchings.


>     Jack escapement and repetition spring tension is felt by the pianist, but
> very few of them can describe what they are feeling. Consistentcy is all
> important in this area, positive action is important, but sudden clicks and
> jumps will definitely bring complaints.

These are felt only on the very softest blows. But then they are critical. Generally if
the keys don't have a lot of lead in them, the repetition lever spring tension can be set
fairly weak and still ensure excellent repetition speed and reliability.


>     In my experience the Japanese factory techs are maticulous in these
> areas, to fine tune any action it must be remembered that the action must
> be regulated twice, due to the inter-active nature of hammer height, rep
> spring tension, rep lever height,and jack position. Once all is well with
> the action stack, then is the time to set the after touch, it needs to be
> clean and solid to the touch. My final check is to check the consistency of
> dip, this will quickly show any errors. Wide after touch can mask a
> multitude of sins.
> Roger

I didn't/don't really set "aftertouch" as such. Each action design and/or installation is
going to have a certain set of "ideal" parameters. Somewhere someone has decided just how
much hammer travel there should be and they have set some fixed key-to-hammer lever ratio.
So, working within these parameters, I set key travel (dip) and then made sure that
aftertouch was correct and uniform by being certain that the rest of the action parameters
were absolutely correct and consistent.

-- ddf