Req info: key dip/carpal syndrome

[stanwood]

Roland,

Carpal Tunnel Syndrome is complex and can result from a combination of
factors.  In my experience the mechanical properties of the action can play
a central role,  also the technique of the pianist and their physical
qualities are important.

A key dip of less than 3/8 with normal aftertouch with a standard blow of 1
3/4 indicates to me that the Strike Weight Ratio is 6.5 or higher.  This
means the hammer is moving faster in relation to the key than is normal for
a properly set up Steinway.  Normal Strike weight ratios for NY Steinway are
generally close to 6.0 and for Hamburg close to 5.5 on the average.
Actions with high ratio numbers are intolerant of any excess hammer weight.

If you imagine a piano key is like a catapult with a short lever on one side
and a long lever arm on the back side.  The longer the lever arm on the back
side, the less distance the front has to move down for the back to move up a
certain distance.  The farthur out the weight is on the back end of the
lever, the more force it takes to move that weight.

I would suggest getting your strike weight ratio down to a normal level by
using a knuckle that is 17mm out from the hammer center pin or more drastic
measures such as moving in the capstan line.  If the Strike Weight Ratio is
5.5 the action should dip out at .390"

A big variable in Steinways is Key Ratio.  This should always be measured
and figured into the big picture.

David C. Stanwood


>From: Rolland Miller <70642.3604@CompuServe.COM>
>Subject: 
>
>Hello list,
>
>About ten years ago I read/heard some opinions that a shallow key dip could
lead
>to muscular problems at the players finger joints and hands.
>
>Does anyone remember or know if the muscular problems were believed to be a
>result of shallow key dip itself, or if they were believed due to the lack of
>aftertouch?
>
>This is in regard to the Steinway B of earlier posts. I may have to reduce the
>key dip to shallower than 3/8" to get the regulation to work out.  I want to
>make sure I don't leave the customer with a potential physical problem.
>