Equal-Tension Scales

[Delwin D Fandrich]

As well, Frank Morton had quite a lot to say about equal tension scales in Piano
Tone Building (1916 - 1919). 

And I've been designing them since the mid 1970s.

I might mention, though, one does need to be specific when discussing "equal
tension" scales. Both equal "unison" tension and equal "string" tension scales
have been tried. For the most part, piano designers have given up on the equal
string tension scale since it yields some pretty rough breaks between string
types, i.e., tri-chord steel to bi-chord wrapped and bi-chord wrapped to
mono-chord wrapped. Even though Frank Morton was a strong advocate of the equal
string tension scale, even he allowed that it would be good practice to deviate
from this by raising the tensions of the bi-chords and mono-chords some.

Nor is it really desirable to religiously follow the equal unison tension rule
through the whole scale. Doing so will result in some pretty high tensions on
the bass scales. Consider, for example, a scale with a fairly moderate
individual string tension of 160 lbs (72.6 kgf). A true equal unison tension
scale would have all of the wrapped bi-chords at 240 lbs (109 kgf) and the
mono-chords at 480 lbs (218 kgf). While it would be physically possible to build
such a piano (at least in longer sizes) it wouldn't really sound all that great.


Del

| -----Original Message-----
| From: pianotech-bounces at ptg.org 
| [mailto:pianotech-bounces at ptg.org] On Behalf Of Joseph Garrett
| Sent: December 18, 2006 8:28 AM
| To: pianotech
| Subject: Equal-Tension Scales
| 
| Frank said: "Someone posted a comment about equal-tension 
| scale design. I believe that I was the first to design such a scale."
| 
| Frank,
| No, I don't think so...not unless you're 150, or so, years 
| olde.<G> Collard & Collard did it. So did Chickering. There 
| were probably many more who tried it. Most of what we do, 
| today, is simply a re-discovery of things done in the past, IMO.
| Regards,
| 
| 
| Joseph Garrett, R.P.T.
| Captain, Tool Police
| Squares R I
| 
| 
|